With Flowers Slide 1 Houseplants and Landscaping

Herbaceous Plants

Houseplants and Landscaping

With Flowers

Houseplants

Houseplant Needs

• Light

• Temperature

• Water

• Humidity

• Nutrients

• Maintenance

Light (whether sun or artificial)

• Quantity = intensity x duration

• Quality = spectrum of wavelengths

Light - Quantity

• Affected by

– Direction of light

– Placement in room

– Season

– Duration of exposure

Light - Quality

• Sun emits spectrum of wavelengths

• Not all wavelengths are needed by plants!

– Red & blue (blue-green) for photosynthesis

• All colors affect appearance!

Artificial Light

• Is it sole source or supplemental?

• Should provide red, blue, violet, green and

yellow wavelengths for best growth and

appearance

• 12-16 hrs daily

• Check wattage and spectrum

Artificial Light - Types

• Fluorescent

– Most are cool, (blue); need cool and warm combo

– Short useful life (1 - 2 years?)

– Full spectrum $$ but worth it if sole source of light

• High-intensity Discharge (HID)

– Good quantity and quality but $$$

• Light Emitting Diodes (LED)

– Good quantity and quality

– Very energy efficient!

– Can last for decades

LED Lights in Greenhouse

Different types of LED lights

Light Intensity

Each plant has different needs for light intensity. Too much light can cause bleaching and

yellowing of leaves. May also cause drought stress from heat (scorching, wilting).

Light Intensity

If there is not enough light, plants will get leggy and stretch towards the sun. This is called

“etiolation.”

Light Intensity

• Low Light

(75 foot candles or 800 lumens)

– North window: few feet away

– East/west window: 3-10 feet away

– South window: 15-20 feet away

Light Intensity

• Medium Light


– North window: directly in front

– East/west window: a few feet away

– South window: 3-10 feet away

Light Intensity

• High or Bright Light


– East/west window: directly in front

– South window: up to 5 feet away

Light Intensity

• Direct (1500 candles)

– South window: directly in front

Temperature

• Regulates all plant processes

– Generally, higher temps = faster activity

• Optimum depends on species

• Night Temps about 10ºF lower

• Avoid extremes, drafts

• Related to humidity

– Warmer air holds more moisture

Temperature

Day temperatures 60-75 degrees F

Night temperatures 5-10 degrees lower

Relative Humidity

• Relative to Temperature

• Amount of moisture in the air

• RH too low – transpiration rate is fast

– wilt, scorch, leaf drop

• RH too high -– transpiration rate is slow

– not common for houseplants!

– soil stays too wet too long > root rot

Humidity

• Optimum for most plants = 35-45% RH

• Home often drops to 15% RH in winter

• Raise humidity by

– Humidifier

– Grouping plants

– Pebble tray

– Terrarium

– Misting???

How Often Should I Water?

• Plant species

• Rate of transpiration

• Pot size relative to size of root system

• Media’s water-holding capacity

How To Tell When to Water

• Feel soil with fingers

• Lift pot to assess weight (dry = light)

• Self-watering pots

Moisture meters?

• Most home versions not very accurate

…And they’re expensive, and often goofy-looking.

Proper Watering Techniques

• Apply enough so that some drains out

• Elevate pots to prevent re-absorption

• Water at room temperature

• Avoid softened water (sodium salts)

Fertilizer

• Needed to supply mineral nutrients

• NPK needed in greatest quantity

• Deficiency symptoms depend on nutrient

– Stunting, discoloration, scorching

Fertilizer Products

• Many products available

– Liquid

• once/month or each watering?

• available immediately

– Solid

• controlled-release (slowly available)

• sticks (slowly available)

• soluble (immediately available)

• Follow label rates!

Over Fertilizing

• Causes salt accumulation

• White salt crust on soil/pot surface

• Can damage or kill roots

• Flush with water

• Fertilize only during active growth

Houseplant Maintenance

• Re-potting

• Pruning/Pinching

• Vacation and Summer Care

• Pest Inspection

When to re-pot?

• The soil mass is filled with roots.

• Roots appear through drainage holes.

• Plant wilts between normal waterings.

• New leaves stunted.

• Plant tips container

Roots

• White, firm roots..these

are healthy EXCEPT…

• They are pot bound roots.

• You will need to slice

these & remove the

circling roots.

***Healthy roots are firm, white, many root hairs.w/o any odor of rot. Unhealthy roots are brown or blk, brittle or rotted, mushy, smelly.****

That’s better !

This houseplant now

needs a larger pot,

some fresh soil, a

good watering &

it’s all set.

Potting Media

• Use clean, loose, well-drained mix

• Optimum mix depends on species

and container

• Most are combo of peat, vermiculite,

perlite, bark, and/or coconut coir

• Avoid garden soil

– Too heavy, poorly drained

– Pests

Containers

• Size appropriate for plant

• Drainage required!

• Double pot if needed

Pruning and Pinching

• Remove dead tissue

• Promote branching, compact growth

– Cut to outward facing bud or branch

– Pinch soft herbaceous stems

– Use pruners for woody stems

Pest Inspection

• Insects

– Mealy bugs, spider mites, scales, aphids

– Swab, hand pick, shower, insecticidal soap

• Disease (rare in home environment)

• Isolate new plants for a few weeks

Pest Management Strategies

1. Identify problem areas

2. Gather information on

management strategies

3. Develop a list of resources and

suppliers

4. Practice IPM for pest management

IPM = Integrated Pest Management Pest management, including insect, disease, weed and animal, will be covered in separate lectures later this semester.

Outdoor herbaceous plants

Non-woody stems that either die back to ground, or die

completely each year

Herbaceous Plants

•A plant whose stem does not produce woody, persistent tissue and generally dies back at the end of each growing season. In temperate climates it usually dies, either completely (annual herb) or back to the roots (perennial herb), at the end of the growing season •Any of various often aromatic plants used especially in medicine or as seasoning. •More popularly, herbs are “useful” plants, grown for their fragrance, medicinal properties, or culinary attributes. Under this definition, an herb may be herbaceous, like parsley, or woody, like rosemary.

Life Cycles

• Annuals

• Biennials

• Perennials

Herbaceous plants can be classified by their life cycles: Annuals, biennials, and perennials.

Annuals

• Germinate from seed, grow, flower, produce

seed and die within a year

• Winter annuals

– Usually initiate life cycle in cooler times of

year and complete life prior to hot summer

• Summer annuals

– Complete life cycle in spring/summer/fall

• Ex: marigolds, zinnia, petunias

Biennials: (Angelica, foxglove, lunaria)

• Require 2 growing seasons to complete

life cycle

• Establish leaves (often as a rosette) and

root first year

• Flower, set seed and die 2nd year

Perennials

• Herbaceous or woody

• Live more than 2 years

• Some short-lived (e.g.: aster family)

• Individual plants of other species (butterfly

weed, iris) can live many years or even

indefinitely

Simple Perennials

• Possess tap roots

• Usually propagated by seed, division or

cuttings

• Ex: violets

Creeping Perennials

• Can multiply and spread without seed

• Rhizomes or stolons

– Convallaria

– Achillea

– Bearded iris

Creeping perennials can eventually fill in a bed.

• Some perennials produce other

specialized structures to allow them to

overwinter or avoid drought and multiply–Tubers

–Bulbs

–Corms

–Tuberous roots

These types of perennials will be covered in depth during the perennial care lecture.

Perennials and Hardiness

Tender Perennials– Need protection to survive winters in

our climate

• Herbs such as rosemary

• Many bedding plants

Hardy Perennials– Can survive outdoors throughout year

Annuals: Advantages

• Versatile, sturdy, & relatively cheap

• Easy to grow

• Produce instant color

• Provide season long color and

interest!

• Can change design easily

Disadvantages:

• Must be planted yearly

– involves some effort &

expense

• Must be dead-headed for

continuous bloom

• Some look disreputable by late summer

Perennials Pros and Cons

• Pros

– Variety of plants, blooms

and foliage

– Colorful or interesting

foliage can provide interest

even when they are not in

bloom.

– Don’t plant every year = less

expensive

– Ability to specialize in plant

groups

• Cons

– Divide every 3-5 years

– Short bloom period

– Less striking blooms

– Too many choices = design

over time

– More challenging to combine

well

Pro: Less expensive over time; individual perennials are usually more expensive than individual annuals, but since a perennial can live and be useful for up to 5 years or more, the costs balance out. Plant groups based on environment: sun/shade, moist/dry…. Cons: Too many choices: HUGE number of species available, plus many varieties/cultivars within each species. These may not all be available locally, but check internet, catalogs. Design challenge: providing blooms season long.

Color – Warm colors

Flower color can have a big impact in your garden. Red is a “hot” color and attracts attention. It can point the way and leads your eye down this path. Avoid using hot colors

such as red, orange or gold in areas you want people NOT to notice.

Flower color can have a big impact in your garden. Red is a “hot” color and attracts attention. It can point the way and leads your eye down this path. Avoid using hot colors such as red, orange or gold in areas you want people NOT to notice.

Color: Cool colors

Combinations of blue, white and pink can be very restful and cool. Even on a hot

deck, these colors make it seem cooler. Imagine red and orange flowers and the

feeling of heat becomes more intense for an already hot deck.

Combinations of blue, white and pink can be very restful and cool. Even on a hot deck, these colors make it seem cooler. Imagine red and orange flowers and the feeling of heat becomes more intense for an already hot deck. Colors evoke feelings; think about which feelings you wish to convey in your garden.

Color: complentary

Complimentary colors of orange and blue make a nice contract. Notice how the hot orange catches your eye. Blue and purple, the cool colors, recede and fade away. In the evening, blues

and purples are easily lost.

Complimentary colors of orange and blue make a nice contract. Notice how the hot orange catches your eye. Blue and purple, the cool colors, recede and fade away. In the evening, blues and purples are easily lost.

Color - Foliage

Foliage will be around much longer than blooms on perennial plants. Some plants have more attractive foliage than they do blooms. Make use of these in landscape.

Wildlife – Nectar, pollen, seeds

Flower gardens are an important source of food for various creatures, including butterflies and birds. They provide nectar and seeds.

Cold Hardiness

55

USDA Cold Hardiness Zone map indicates what the average low temperature for that area is. Most of Southwestern Indiana is in Zone 6b, meaning that we can expect the AVERAGE low temperature for the winter to be between -5 and 0 degrees F. We use this map to avoid planting plants that are not cold-hardy, like bananas and palm trees. Note that this is an average; we can always get a cold snap where the temperatures dip below this range.

Heat Hardiness

Cold is not the only factor determining if plants will survive and thrive. •Heat impacts plants, especially during seasons of drought •Extreme cold can kill plant instantly •Effects of heat damage more subtle –Heat damage can first appear in different parts of plant

•Flower buds may wither •Leaves may droop or become more attractive to insects •Chlorophyll may disappear so leaves appear white or brown •Roots may cease growing

–Plant death from heat is slow and lingering •Plant may survive in stunted or chlorotic state for years •When desiccation reaches high enough level, enzymes that control growth are deactivated and plant dies

Heat Hardiness

57

AHS Plant Heat

Zones Map

The AHS (American Horticulture Society) put together a Plant Heat Zone Map. This map indicates the average number of days per year where the temperature is expected to go above 86 degrees F. Most of the Tri-State is in Heat Zone 7, meaning we can expect between 60 and 90 days where the temperature is above 86 degrees. Please note that this map does not indicate the average high temperature. However, it is safe to assume that the more days you have over 86 degrees, the more likely you are going to have some very hot weather, which may damage some plants that require cooler weather.

Microclimates

A microclimate is different than the regional hardiness zones we’ve been discussing. A microclimate refers to the environmental conditions around your plant. These conditions are different from one part of the landscape to another. For example, some plants are shade-loving; they will not survive if planted in full sun. Hostas, impatiens, and astilbe are examples. Others require full sun, such as purple coneflower, daylilies, and sedum.

Microclimates can change rapidly

Microclimates can change radically, quickly. Storms knocking over a tree can destroy shade garden that was depending on it.

General Management of Flower Beds

Although there are specifics for caring for different types of herbaceous ornamentals (annuals, perennials, grasses, etc.), there are some general considerations that are universal to all of them. Proper management begins with site preparation.

Site Selection

• Choose a suitable

site:

– sun, shade, wet, dry

– close to water source

– away from shallow

rooted trees and

shrubs

Examine proposed bed locations during the growing season (lots of sunlight under a maple tree…in winter!). Most annuals prefer full sunlight. Perennials run the gamut from requiring full sun to full shade; choose plants properly. Shallow-rooted trees and shrubs will compete with flowering plants for water and nutrients. The invasive roots will also make soil amending and digging difficult.

Kill Existing Vegetation

• Ideally the season prior to planting

– Chemical: Roundup or other non-selective

herbicide

– Smother for 3 to 4 weeks:

• Black plastic

• Newspaper (five sheets thick)

• Carpet remnants

• Turn over or remove sod

Site preparation, especially early weed control, should begin at least 1 season before planting. Perennial weeds may require several herbicide applications to kill; weed seeds in the soil will germinate once they are exposed to sunlight. Glyphosate (Roundup) should be sprayed on site to kill weeds and turfgrass. Glyphosate kills almost anything green it lands on; however, once it touches the soil, it is deactivated. This means that there is no chance of injury to plants because of soil contamination. Weed control will be covered later in this semester. Smothering the weeds can be done in home gardens, but is not a satisfactory option for commercial landscape beds.

Site Preparation

• Check & adjust drainage

– Raised beds may be necessary

• Soil tests are recommended!

– Determine proper amounts of fertilizer to

apply

– Determines soil pH (level of acidity)

• Use lime to raise pH

• Use sulfur to lower pH

Check soil drainage by running a percolation test: dig a hole 1 foot deep, 1 foot wide. Fill with water, let it drain out for 24 hours. Then, refill and allow to drain. Measure amount of water lost over 6 to 8 hours. Adequate drainage rate is 1 inch of water per hour; less than 1/2 inch per hour is considered poorly drained, and may be suitable only for wet-site plants. Loss of water more than 1.5 to 2 inches per hour is overly well drained, and may only suitable for dry-site plants, or will need frequent irrigation. Soil testing prior to planting is essential. It provides information on amount of nutrients currently in the soil (especially phosphorus and potassium), which in turn determines the type of fertilizer needed and the amounts. Soil pH (measurement of soil acidity) determines availability of micronutrients (trace elements), as well as what types of plants will survive in this area. Depending on the pH level, you may be required to add lime or sulfur to adjust it. Fertilizer should be applied to all beds when the soil is prepared in early spring. Add 2 to 3 pounds of a general purpose fertilizer such as 5-10-5 or similar analysis per 100 square feet of bed area. One pound of dry fertilizer is about equal to 2 cups. Do not over-fertilize, especially with nitrogen, or you will stimulate over production of foliage, with a decrease in flowering.

Amend soil with organic matter

– Incorporate 3-4” of

composted organic matter

– Spade or till in 8-12” deep

• improves soil aeration

• improves drainage

• encourages healthier root

system

• easier to plant and manage

Rototilling is much easier than hand-digging; however, most rototillers only disturb soil about 4 to 6 inches deep. For perennials and bulbs, want soil loosened much deeper. Important to amend the entire bed, and not just the planting holes. If only the planting holes are loosened and amended, then water will collect here and not drain out, causing root rot. Consider doing this every 3 to 5 years, or every time perennials are divided.

Using Annuals and Perennials in the

Landscape• Have a plan!

• Group or mass plants to get best visual display

• Consider plant characteristics

– size/scale, texture, color (foliage and flowers), bloom time

• Goal: variation without chaos

This is chaos!

4 ft. 4-5 ft.4-5 ft. 5-6 ft. 4 ft.

2-3 ft.2-3 ft.2-3 ft.

3 ft.3 ft.

1-2 ft. 2 ft.1-2 ft.

6-10 in.

1 ft.

8-12 in.10-15 in.

Plant Groupings

Background: large groups of tall plants

Foreground: shallower, wider groups of smaller

plants

Select groups as to season of flowering and

if annual, biennial, or perennial.

• Shape bed by slightly raising or

mounding towards the center or back

– provides better drainage

– positions plants so they can be viewed

more easily

Planting

• Plant while soil is moist - not

saturated

• Plant during cooler part of day -

evening

• Water in immediately

• Apply light mulch 2 - 3 inches thick

– shades out weed seed

– moderates soil temperatures

– holds moisture

Mulching

• Prevents weed seed germination

• Protects plants from lawn (encroachment and mowing)

• Keeps soil from drying out

• Keeps soil cool in summer

• Winter mulching prevents frost heaving

Mulch: peat moss, wood chips, shredded bark, leaf mold, pea gravel, river rock. Can use landscape fabric (weed cloth) but weeds may germinate in top of it. Also, organic matter cannot reach soil in presence of landscape fabric. Avoid black plastic: it prevents water and air from reaching root system, great place for voles to hide. Goal is to maintain 2 to 4 inches of mulch. If mulch is < 2” won’t be effective weed control, won’t prevent soil from drying out. If mulch is > 4” it may attract voles etc. & can promote crown rot. Do not place mulch against stems…will cause stem rot. Winter mulch: applied after ground freezes. Prevents “heaving” of the plant due to repeated freeze and thaw cycles.

Frost heaving

Frost heaving occurs with fluctuating freezing and thawing. Ice crystal formation can actually force young plants, not fully established, out of the ground.

Care and Maintenance

• Use mulches to control weeds and erosion

• Use winter mulches to protect perennial

structures

• Add 1 pound of 5 -10-5 per 100 square feet

each spring

• Add 1 pound of 5-10-5 per 100 square feet

as side-dressing

• Test your soil every 3 to 5 years

1/2 to 1 pound of 5-10-5 per 100 square feet used as a side dressing will be sufficient. Side dressing can be applied during the active growing season; this is especially crucial for annuals, which are heavy feeders. Do not let dry or concentrated liquid fertilizer contact foliage or flowers. Water thoroughly after applying fertilizer. To help plants get ready for the coming dormant season, do not fertilize after August 1.

Watering

• Gardens should receive 1

inch of water per week.

• Water early in the day if

overhead watering… foliage

should be dry at night.

• Group plants by irrigation

needs (dry-site tolerant vs.

those with heavier moisture

needs)

Wet foliage at night promotes disease problems. Soaker hoses can be run through flower beds to avoid overhead watering. Hoses can be buried under mulch to hide them. Run them long enough for water to penetrate 8 to 12 inches deep. Beware of voles, which can chew holes in hoses. Group plants on water needs! Dry-site plants should be separated from those that need regular and frequent irrigation: if combined, dry-site plants will rot, and wet-site plants will wilt.

Maintenance:

• Water regularly

• Fertilize based

on soil tests

• Daily walk through to monitor for problems

• Remove pests by hand or mechanically

• Use insecticides/fungicides only when

needed

Maintenance

• Weed control is best done by:

– Use of mulch

– Hand pulling

– Shallow cultivation

Maintenance continued:

• Weed control with herbicides

–Preemergence herbicides

• Treflan – Preen, others

–Post emergence for grassy weeds

• Sethoxydim – Poast, Grass-getter

• Fusilade – Grass-b-Gone

–Post emergence for broadleaf weeds

• Roundup gel (rub on)

Preemergence herbicides control mostly annual grass weeds, although a few broadleaves can also be controlled. Post emergence herbicides are restricted to grass killers; the broadleaf weeds are too closely related to the annual flowers to use post emergent broadleaf herbicides.

Autumn Clean-up

• Cut back after stems/

leaves die.

• Label “slow to emerge”

plants

• Tag plants for spring

division/stagger dividing.

• Remove debris.

Avoid temptation to cut back foliage immediately after bloom. Perennials and bulbs need to photosynthesize to make food for next year. Without foliage, plants may not bloom, or even survive, for next year. This includes doing silly things like braiding or wrapping the foliage. Label perennials and bulbs, so they are not disturbed or damaged by planting other plants. If staggering the cycle of perennial division (so you don’t have to do entire bed all at once), tag the clumps that are to be divided. Removing debris (dead foliage, etc.) helps prevent disease & insects pests from surviving to the next year. Cut back perennials to ~ 3-4”, remove annuals completely. Compost debris if possible. It is a judgment call not to do a thorough clean-up in order to preserve butterfly chrysalids, and/or provide shelter & seeds for birds etc.

Using Annuals in the

Herbaceous Garden

Adaptation to Environment

Failure to match plant’s needs with site will lead to poor

blooming, survival, and aesthetics.

For most success, the annuals you choose should be adapted to the environment of your garden. Failure to match site with plant’s needs will lead to poor blooming, poor survival, and poor aesthetics.


• Soil moisture

– Almost all annuals do best in moist,

well-drained soil.

– Only a few large tropicals will tolerate wet

soils – canna lily, elephant ears, purple heart

Let’s begin with soil moisture. I started to create three lists, one for annuals that like wet soils, one for moist soils, one for dry soils. I quickly realized there would be no plants on the list for wet soils. There are simply no standard annuals that will do well in wet soils. If the homeowner has wet soils, and they want something temporary, they will need to use the large tropical – there are a few, shown here, that will do OK in wet soils. There are some perennials that do well in wet soils also, but there are no annuals that grow well.


• Soil fertility

– Some annuals tolerate poor soil. Often too

much nitrogen fertilizer will reduce

flowering.

• Cosmos

• Dahlia

• Helichrysum (strawflower

and licorice plant)

• Ipomoea (morning glory)

Helichrysum bracteatum -

strawflower

The other soil issue is fertility. Some annuals will tolerate poor soils. Some even decrease flowering if soil nitrogen levels are too high.

Soil fertility

– Some annuals may

need extra fertilizer to

do their best.

• Argyranthemum (Marguerite

daisy)

• Catharanthus (annual vinca)

• Celosia (cockscomb)

• Pelargonium (geranium)

• Petunia

• Salvia splendens (scarlet

sage) Salvia splendens with

Senecio cineraria (dusty miller)

There are other annuals that may need extra fertilizer to flower their best, even more than the standard recommendations that we’ll discuss in a few minutes.


• Light– Most annuals will tolerate full sun, especially if given ample

moisture

– Many will tolerate half day (3-4 hrs) sun

– The list of shade tolerant annuals is still small, mainly annuals grown for foliage.

• Begonia

• Impatiens

• Torenia

(wishbone flower)

• Mimulus

(monkey flower)

• Browallia

(bush violet)

Dichondra ‘Silver Falls’

Foliage

• Alternanthera

• Caladium

• Dichondra (‘Silver Falls’)

• Hypoestes (polka-dot plant)

• Iresine (bloodleaf)

• Oxalis (shamrock)

• Perilla

• Solenostemon (Coleus)

Light is the other issue. Most annuals will tolerate full sun, many will tolerate part sun, but the list of shade-tolerant is still small. If you want flowers in shade, it’s still begonias and impatiens. There are more varieties of begonias and impatiens, but they are still the main players. There are a few others that will flower in shade, but I don’t see them becoming major players. There are many new annuals that are foliage plants and they will often do well in shade.

Foliage Color and Sun Exposure

• More shade produces:

– Leaves with more chlorophyll and thus more green.

– Larger leaves.

• More sun produces

– Leaves in which non-green colors predominate. Solenostemon ‘Gay’s Delight‘ (Coleus)

Sun leaf shade leaf

There are some issues when growing foliage plants in shade. These two leaves were taken from the same plant. One was from a branch in full sun; the other from the shade. You can see how a homeowner, if they saw these two leaves on the same plant or in a large planting of the same variety, would wonder what was going on - Is it a fertilizer issue? What’s wrong with the plant? - when it is really a sun/shade issue. You’ve all figured out by now that the large green leaf is the one from the shade. Shade leaves produce more chlorophyll and will be greener. Leaves in the sun have less green so the yellow, pink, purple, peach colors in the leaves will be more prominent. But if the homeowner bought the plant looking one way and 4-6 weeks after planting it had changed color because it was in an environment different from the one it was in at the garden center, they would be very concerned.


• Temperature

– Some annuals grow best in cool weather.

Will suffer in hot weather.

– Watering and shade may help, but not

necessarily

• Antirrhinum

(snapdragon)

• Dianthus, non-hybrids (annual

pinks)

• Lobelia

• Phlox

• Viola (pansy) Lobelia

The last issue is temperature. This is the one we usually don’t think much about. We think about it early in spring when we realize we can plant pansies and they will tolerate the cool weather. Some people may think about snapdragons but that’s about the extent of it. There are some annuals that will tolerate cold temperatures, but there are some others that may cause problems

Temperature

– Other annuals grow best in cool weather but will survive hot weather.

– Usually flowering decreases and stops altogether, but resumes when temperatures drop in autumn.

Osteospermum

There are several annuals that won’t tolerate freezing weather, they can’t be planted out early, and they need summer temperatures to be cool to do their best. Let me show you this osteospermum (top photo) as an example. This is a fairly new annual with really gorgeous flowers. They’re at least 3” wide, with a purply-blue iridescent center. Every photo of this plant you will see shows it in full flower, something like you see in the photo. Unfortunately, (bottom photo), this is usually what you see in the heat of a Kentucky summer. You’ll have a few flowers but it’s not anything like what you expect (osteospermum is the medium green plant in center of photo). Here are unrealistic expectations again – what the homeowner has been lead to believe and the difference they might experience from one summer to the next. In a cool summer, it flowers well, in a hot summer, the flowering stops as the heat comes on.

• Argyranthemum

(Marguerite daisy)

• Dianthus, hybrids

(annual pinks)

• Diascia (twinflower)

• Lobularia (sweet alyssum)

• Osteospermum

• Torenia

(wishbone flower)

• Lathyrus (sweet pea)

Annuals with Decreased

Flowering in Hot Summers

Lobularia

Here are some other plants that don’t flower well in hot summers. I’ve seen diascia just limp along all summer and then put on a spectacular show when it cools down in September. One of the vines – sweet pea – also doesn’t flower well in hot summers.

Problems from incorrect selection

• Root rot – soil too moist

• No or reduced flowering – Too little light

– Too hot

– Soil moisture level inconsistent

– Too much nitrogen or not enough fertilizer

• Leaves not expected color– Too much or too little light

– Scorch due to inadequate water

• Plant deteriorates in mid-summer– Not adapted to Indiana’s hot,

humid summers

As you can see, there are lots of problems that can come from placing annuals in the wrong location, expectations that aren’t met because of site selection or because of the summer weather.

Bad Habits

• Reseed to the point of being weedy– Celosia, Spicata type

(wheat celosia)

– Cleome

– Perilla, non-hybrids (shiso)

– Ricinus (castor bean)

– Verbena bonariensis(tall verbena)

• Pre-emergent the next year may help

Wheat celosia seedlings

Let me talk about a few bad habits you need to be aware of. Some annuals reseed to the point of being weedy. The plant in the upper photo is wheat celosia. In the lower photo, all the plants with colored foliage are seedlings. When small they are easy to pull, but they’ll keep coming up all summer. The homeowner needs to think ahead about how they’ll handle this problem – a pre-emergent can help. Unfortunately, deadheading is very difficult on many of these plants, as I’ll describe in a few minutes.

Bad Habits

• Ugly if not deadheaded– Ageratum

– Argyranthemum(Marguerite daisy)

– Celosia

– Pelargonium (geranium)

– Salvia

– Tagetes (marigold)

– Zinnia

– Solenostemon (coleus)

– Perilla (shiso)

– Ocimum (basil)

Salvia splendens

Another problem is annuals that just look ugly if you don’t keep them deadheaded. Sometimes the flowers will drop off and you have a stalk sticking up, like you have in this salvia, sometimes the flower clusters are large and just look bad. Some of the foliage plants like coleus and the ornamental basils will send up flowers late in the season and most people prefer to keep these cut off.

A few do not need deadheading

• Angelonia

(summer snapdragon)

• Cuphea

• New generation

Petunias

• Melampodium

(medallion flower)

• Oxalis (shamrock)

• Penstemon (beardstongue)

• Scaevola (fanflower)

• Zinnia angustifolia

(narrow-leaved zinnia)

Angelonia

Zinnia angustifolia

Fortunately there are a few annuals that don’t need deadheading, so these are some you might recommend for an easy-care planting.

Deadheading

• Deadheading is the removal of flowers after they have faded

• Plant does not produce seeds

• Will often spur plant to produce more flowers

There are some things we do to annuals to keep them looking good and one of those is deadheading. In annuals, this will often spur the plant to produce more flowers. You also cut off the flower before the fruit and seed can form (reducing reseeding the next year). Deadheading is done as you see here – you cut off the faded flower at the base of the stalk right above a leaf.

What to look for when buying:

• The plant should be:– rosette-like - short, stocky, leaves

arranged in a rosette like pattern,

vs. tall and leggy with leaves spaced

out across stem

– healthy looking - deep/bright green,

firm, lustrous; not yellow, brown,

twisted, curling, sticky, etc.

– Plant is branching

– Not be in flower - energy directed

towards root formation

Picking Good Plants

• Roots fill soil ball

• Healthy roots - white, fuzzy,

abundant; not brown, slimy,

or wrapping in circles, or too

few

• Root ball should be moist -

but not soggy; and not water

stressed

When you go to the garden center there are several things to look for. If you talk to a group of gardeners, ask them if they’ve ever purchased an annual, taken it out of the pot to plant it and found that half the soil remained behind in the pot. Most of them have. You don’t want that to happen. You want as many roots on the plant as possible, for the roots to fill the whole rootball. It’s perfectly acceptable to gently and with care pull the plant out of the pot and look at the roots to make sure they are healthy and fill the soil ball. Of course, make sure the plant has good color, with no pest. You should also look to see if the plant is branching. This is especially important on foliage plants – you don’t want a plant that’s tall and skinny, you want one that’s full, but it is important on flowering annuals also.

Before Planting

• Pinch to encourage

branching

– Especially needed on

plants grown mainly for

foliage

• Pinch off any flowers,

so plant puts energy

into rooting.

Many flowering annuals form flowers at the tip of the growing stem, so the more growing stems you have the more flowers you will have.

Perennial Flower Gardening

This slide show was based on a lecture by Eileen Nelson, UW Department of Horticulture

Bulbs

• Includes corms, tubers, rhizomes,

and tuberous roots

Corms

swollen stem base (basal plate)

no scales

Tubers

underground stem used for storage

no basal plate, no covering of dry leaves

Tuberous roots

true root

Rhizomes

thickened stems growing at or below the soil surface

Bulb planting is not glamorous

• Site preparation: Preferably 1

season before planting.

• Dig deeply! Mix in organic

matter.

• Soil test: bulbs need high

phosphorus levels.

Site preparation: Preferably 1 season before planting. Dig deeply! Mix in organic matter. Soil test: bulbs need high phosphorus levels.

Planting depth

Bulbs must be planted deeply enough. Rule of thumb: plant at depth ~ 3 times bulb’s largest diameter. Depth = where bottom of bulb will sit.

Pointy side up!

Be sure to plant bulbs with pointy side up, and roots down. Plant wastes energy if bulb is planted sideways, upside down, etc.

Rhizomes: Iris

Irises are an exception. Iris rhizomes must be planted so rhizome is right at soil surface. Planting too deeply will prevent blooming.

Mass planting is best

Mass of bulbs planted in individual holes

Bulbs look best planted in masses of similar plants and colors. Some people dig individual holes…

Masses of small bulbs planted in clusters

…or you can plant in clusters. This is especially good for small bulbs. Again, masses look better than individual plants.

Planting bulb bed with multiple species

Sometimes, planting an entire bed at once is easiest and most appealing.

Laying out the bulbs

Bulbs being laid out

Finished planting before backfill

Notice the variety of bulbs being used.

End results the following spring

The following spring.

Spacing

Proper spacing is important. Too far apart, not very attractive. Too close, will compete with each other and reduce blooming. See HO-86 for table with spacing info.

Dividing Perennials

• Control size

• Rejuvenation

• Increase numbers

• Plant sale!!!

The three main reasons for dividing perennials are to control the size of the plants, to help rejuvenate them, and to increase their number. Dividing and replanting keeps rapidly spreading perennials under control. Dividing will rejuvenate old plants, keeping them vigorous and blooming freely. Dividing perennials is an easy and inexpensive way to gain additional plants for your garden or to share.

When to Divide

• Reduced plant size

• Reduced flowering

• Dead areas

• Sparse bottom foliage

• Depends on the species

Spring blooming plants divide in the fall…

… fall blooming plants divide in the spring.

Overgrown dahlia clump

In general, it is best to divide spring and summer blooming perennials in the fall, and fall bloomers in spring. By dividing the plant when it is not flowering, all the plant’s energy can go to root and leaf growth. Fall division should take place between early September in the uppermost Piedmont and mid-to late October on the coast. Allow at least four to six weeks before the ground freezes for the plants to become established. If you divide in the spring, allow enough time for roots to settle in before hot weather. Spring division is ideally done in the early spring as soon as the growing tips of the plant have emerged. Spring divided perennials often bloom a little later than usual. Never divide perennials on hot, sunny days. Wait until a cloudy day, ideally with several days of light rain in the forecast. Most perennials should be divided every three to five years. Some perennials such as chrysanthemums and asters may need to be divided every one or two years or they will crowd themselves into non-flowering clumps of leaves and roots. Bleeding hearts and peonies may never need to be divided unless you want to increase your stock. Signs that perennials need dividing are flowers that are smaller than normal, centers of the clumps that are hollow and dead, or when the bottom foliage is sparse and poor. Plants that are growing and blooming well should be left alone unless more plants are wanted.

Preparation

• Before dividing…

• Water plants thoroughly

• Prune stems and foliage

Water plants to be divided thoroughly a day or two before you plan to divide them. Prepare the area that you plan to put your new divisions in before you lift the parent plant. Prune the stems and foliage to 6 inches from the ground in order to ease division and to cut down on moisture loss.

Lifting

• Use sharp shovel or

spading fork

• Cut in on all sides of

plant

• 4 to 6 inches from crown

• Pry under plant

Use a sharp pointed shovel or spading fork to dig down deep on all four sides of the plant, about 4 to 6 inches away from the plant. Pry underneath with your tool and lift the whole clump to be divided. If the plant is very large and heavy, you may need to cut it into several pieces in place with your shovel before lifting it.

Separation

• Remove loose soil

• Remove dead leaves and stems

• Note root system of plant

– Spreading

– Clumping

– Rhizome

– Tuber

Shake or hose off loose soil and remove dead leaves and stems. This will help loosen tangled root balls and make it easier to see what you are doing. Perennials have several different types of root systems. Each of these needs to be treated a bit differently.

Separation: Spreading root

system

• Many slender roots from

center of plant

• Plants can be invasive

• Cut with shears or pulled apart by

hand• Asters, bee balm, lamb’s ear, purple coneflower,

many common perennials

Spreading root systems have many slender matted roots that originate from many locations with no distinct pattern. Plants with spreading root systems include asters, bee balm, lamb’s ear, purple cornflowers and many other common perennials. These can crowd out their own centers. Some can be invasive unless divided frequently. They can usually can be pulled apart by hand, or cut apart with shears or knife. Large, vigorous plants with thickly intertwined roots may need forceful separation with digging forks. Put two forks back to back in the center of the plant and use them to pry the pieces apart. Divide the plants into clumps of three to five vigorous shoots each. Small or weak and woody divisions should be discarded. Discard the center of the clump if it is weaker than the outside edges.

Separation: Clumping root system

• Many fleshy roots from crown of

plant

• Can crowd own centers

• Keep one bud/eye with

each division• Astilbes, hostas, daylilies,

ornamental grasses

CLUMPING ROOT SYSTEMS originate from a central clump with multiple growing points. Many have thick fleshy roots. This group includes astilbes, hostas, daylilies and many ornamental grasses. It is often necessary to cut through the thick fleshy crowns (the central growing area between the roots and the leaves and stems of the plant) with a heavy, sharp knife. You can also pry apart these roots with back to back digging forks. Keep at least one developing eye or bud with each division. If larger plants are wanted, keep several eyes.

Clumps have been separated. Minor root damage is OK.

Clumps have been separated. To separate with a minimal of root damage is time consuming.

Separation: Rhizomes

• Horizontal stems, primarily bearded iris

• Divide after flowering through fall

• Cut and discard rhizome sections > 1 year

• Inspect for disease and insect damage

• Cut back leaves to ‘fans’

• Replant with top of rhizome above soil

level

Rhizomes are stems that grow horizontally at or above the soil level. Bearded irises are the most common perennial with this type of root system. Divide irises any time between a month after flowering until early fall. Cut and discard the rhizome sections that are one year or older. Also, inspect rhizomes for disease and insect damage. Damaged rhizomes should be trimmed and treated, or discarded if too badly damaged. Iris divisions should retain a few inches of rhizome and one fan of leaves, trimmed back halfway. Replant with the top of the rhizome just showing above soil level.

Mass of rhizomes

Mass of iris rhizomes before separation.

• Iris rhizomes after separation

• Each piece has a bud (“eye”), plus a cut-back fan

Iris rhizomes after separation. Each piece has a rhizome with an “eye”, plus the beginnings of a fan of foliage.

Separation: Tuberous roots

• Enlarged roots for storage

• Divide with sharp knife

• Each root must contain stem tissue and bud• Dahlias

TUBEROUS ROOTS Dahlias are an example of perennials with tuberous roots. The tubers should be cut apart with a sharp knife. Every division must have a piece of the original stem and a growth bud attached. After division they can either be replanted or stored for spring planting.

Plants better left alone

– (Asclepias)

– euphorbias

– oriental poppies

– baby’s breath

(Gypsophila)

– gas plant

(Dictamnus albus),

– Japanese anemones,

– false indigo (Baptisia)

– columbines

(Aquilegia),

– Lenten and Christmas

roses (Helleborus),

Some plants resent being divided and it should be avoided if possible. These include butterfly weed (Asclepias), euphorbias, oriental poppies, baby’s breath (Gypsophila), gas plant (Dictamnus albus), Japanese anemones, false indigo (Baptisia) and columbines (Aquilegia). Lenten and Christmas roses (Helleborus) are very difficult to move when more than a few years old. Usually you can find tiny seedlings around the base. These are easy to move. Lavender cotton (Santolina chamaecyparrus) and several other perennials are actually small woody shrubs and should not be divided. These include perennial candytuft (Iberis sempervirens), lavender, rosemary, southernwood (Artemesia abrotanum), and several other artemesias. These plants often have rooted layers (branches that have developed roots while touching the soil). The layers can be cut off the parent plant, dug up and replanted as though they were divisions.

Winter Protection

• Hardy-perennials will normally survive the winter

with little or no protection.

• In colder parts of the country perennial beds are

often mulched to provide winter protection.

• Wait for ground to freeze before applying winter

mulch. Goal is to keep soil cold.

With Flowers Slide 1 Houseplants and Landscaping

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