Growing Fresh Flowers
Annuals
Annual flowers can be a prime source of color to accent and enliven
a home's landscape. While flowering trees and shrubs provide short bursts
of color, most annuals begin blooming within a month of planting and
flower until frost. The wide range of colors, sizes and species adapted
to either sun or shade makes it possible to plant annual flowers almost
anywhere. Annuals are perfect for beds, borders, rock gardens, window
boxes, hanging baskets or as temporary ground covers and fillers.
Annuals are non-woody plants that complete their life cycle in one
season, ending with seed production. Confusion can arise when an annual
plant reseeds itself and appears to have a perennial habit.
Use in the Landscape
Annual flowers can play an important role in a well-designed landscape.
Compared to most perennial landscape plants, annuals require higher
levels of both maintenance and water, so plant annual beds in easily-accessible
areas and near water sources. Concentrate annuals in beds with other
annuals or plants with similar water requirements. Planting annuals
randomly throughout the landscape not only increases maintenance, but
also lessens the plants' aesthetic impact.
Although annual flowers and plants bring a variety of interesting textures
and forms to the landscape, they are most notable for the color they
provide. Plant simple mixtures of color. Color themes using related
colors, such as red, orange and yellow (warm colors) or green, blue
and purple (cool colors) work well. Warm-colored flowers bring excitement
into the landscape and tend to appear close to the viewer, making the
space in which they are planted feel smaller. Cool-colored flowers,
however, appear more distant, creating a greater sense of garden space.
Cool colors also tend to relax and soothe viewers.
Using shades of one color (including white) is also a popular and attractive
theme. Another pleasing effect comes from using complementary colors
— those colors found directly opposite each other on a color wheel
— such as orange and blue or purple and yellow. These combinations
form high color contrasts and create a lot of excitement and interest
in the landscape. Always be aware of surrounding or backdrop colors
to achieve a coordinated overall design. The best way to set off annual
flower colors and textures is to provide a simple backdrop of green
vegetation.
Annuals are an excellent way to draw attention to building and home
entrances, walkways and outdoor living spaces and to provide homeowners
and visitors with pleasing "up-close" visual and fragrant
experiences. Again, it is important to be selective in placing annuals
so their ability to draw attention is not diluted.
Plant height is another important design consideration. Typically,
a flower border has the tallest plants in the back, medium height plants
in the middle and short plants in the front. An island planting places
the tallest plants in the middle of the bed, surrounded by plants of
decreasing heights.
The style of the annual bed should be compatible with the overall style
of your landscape design. A planting can have either a formal or informal
design, depending on the arrangement of the planting. Formal designs,
for example, tend to be made up of geometric lines and symmetry, with
strong focal points that attract the eye. In contrast, informal designs
have curved, flowing lines and natural forms, follow natural terrain
and create an asymmetrical balance within the planting.
Before planting, the physical characteristics of the site must be evaluated.
Consider the site's soil type, fertility, drainage and its exposure
to sun and wind. Compare site characteristics with specific plant requirements.
(See NebGuide G84-739, Annual Flowers for Nebraska, for a listing and
description of annuals grown successfully in Nebraska.) An annual plant
adapted to site conditions grows and flowers more vigorously and has
fewer pest problems. Some plants intolerant of heat and sun may perform
adequately when planted in part shade.
Annual flowers offer flexibility in landscape design. Any planting
can be changed each growing season, creating an entirely new design.
As a part of their quick change potential, annuals can be used as a
temporary solution in a problem site.
Seeds and Plants
Many annual flowers, such as marigolds, globe candytuft and zinnias,
can be direct-seeded; that is, the seed is planted in the location in
which it will grow all season. Others should be started indoors and
transplanted outdoors at the appropriate time. Some annuals, such as
larkspur, can be fall seeded. Growing seedlings indoors requires proper
light and temperature, a pasteurized growing medium and several weeks
of careful attention. Because it can be difficult to produce quality
transplants at home, many gardeners are better off purchasing transplants.
Flower transplants and vegetable transplants are produced using the
same methods.
When selecting transplants, look for stocky plants with dense foliage
and rich colors. Avoid seedlings that are leggy, yellowish or dry looking.
If possible, check the root system. Most healthy plant roots are white;
avoid purchasing plants with brown or black roots. While it is tempting
to choose blooming plants, it is better to select those that are not.
Soil Preparation
Prepare an annual bed by digging or rototilling 8 to 12 inches deep.
Amend the soil with organic matter, such as well-rotted manure, sphagnum
peat moss, compost or leaf mold. Spread 1 or 2 inches of the organic
matter over the soil and 1 to 2 pounds of fertilizer, such as 5-10-5,
per 100 square feet of bed and incorporate. Do not over-fertilize, which
can cause excess foliage growth at the expense of flowers. Rake the
bed smooth and remove any stones, clods or old plant debris before planting.
Direct-Seeding
Seeds of annual flowers vary in their hardiness and ability to germinate
under certain soil temperatures. Hardy annuals can be direct-seeded
in early spring. Do not seed tender annuals until the soil has warmed
to 60° F. Once the planting bed has been prepared, make a shallow
furrow for planting the seed (Figure 1). Read the seed packet for correct
planting depth. Distribute the seed in the furrow and cover very lightly
with soil or, if your soil tends to crust over, with a fine layer of
vermiculite. Vermiculite will not crust over as soil often does and
it allows better seedling establishment. Water the planting site with
a fine mist to prevent washing away the seed. Keep the bed moist until
the seeds germinate. Newspapers, boards or floating rowcovers can be
placed over the planting site to maintain soil moisture. If using a
board, place a brick under each end to keep the wood from resting directly
on the ground, and remove it when germination begins. Decrease watering
frequency as the seeds begin to germinate. Thin seedlings before they
become crowded. Excess seedlings can be transplanted to other locations
or shared with friends.
Planting Transplants
Although some annual plants tolerate cooler conditions, most should
be planted outdoors only after danger of frost is past. Plant during
the coolest part of the day, preferably when it is cloudy. Moisten plants
before removing them from their containers. If roots are pot-bound,
slightly tear the root ball to encourage spreading.
If you are using plantable peat pots, tear them to allow the roots
to easily break through the sides. Also, tear off the top rim of the
peat pot. This prevents the peat from being exposed to the air where
it will act as a wick and draw moisture away from the soil ball, drying
out the plant.
Set the plants at the recommended spacing and cover them with soil
to the depth of their container. Firm the soil around the roots and
water immediately.
Most plants respond well to pinching at planting time. Pinching, or
removing the early flowers, allows the plant's energy to be used to
establish the plant rather than support flowers. Pinching also induces
branching which will, eventually, increase the number of flowering stems.
For best results, pinch out the first and second set of leaves (Figure
2).
Maintenance
Annual flowers generally require 1 to 1 1/2 inches of water each week.
Be sure the water penetrates to the root zone. Generally, hand watering
is not adequate to supply sufficient and uniform amounts of water. Soaker
hoses or sprinklers are more satisfactory watering methods. Soaker hoses
are the most efficient because there is very little runoff, and evaporation
and soil compaction are slight. Avoid overhead watering, particularly
in the evening. Foliar diseases can be reduced by watering in early
morning, rather than at night.
An annual flower planting may require additional fertilizer during
the growing season. If the soil fertility is low, fertilize plants at
a rate of 1/2 to 1 pound of 5-10-5 per 100 square feet every 4 to 6
weeks. Sprinkle the fertilizer lightly along the row and scratch it
into the soil.
Although most weeds in home plantings can be adequately controlled
with a combination of mulching and cultivation, herbicides are available
for use in annual flower beds. Before spraying, read the label carefully
to determine if the herbicide is safe for use on the plants you are
growing.
Pinch off faded blooms at least weekly to stimulate blooming throughout
the season. Trailing plants, such as fibrous begonia, petunias, pansies
and coleus, can be pruned to keep the plants compact and stimulate additional
blooming. Removing faded flowers prevents the plants from forming seed.
As a result, they will bloom again in an effort to complete the life
cycle.
Annual flowers have relatively few insect and disease problems. However,
specific problems will characteristically develop on some plants. Maintaining
vigorous growth, spacing plants so they receive good air circulation,
planting in a site with good drainage and sun exposure suited to the
plant will usually reduce disease problems. Quick identification of
the problem and application of the proper insecticide or fungicide will
minimize pest damage.
Perennials
Herbaceous perennials are non-woody plants that live two or more years
under local conditions. The above ground parts of these plants are generally
killed to the ground by frost in the fall, but the roots and/or underground
parts live through the winter. Growth is renewed and the cycle begins
anew in the spring.
While perennials do not require yearly replanting, they still require
regular maintenance. For best results, a proper site analysis, soil
preparation and routine maintenance are necessary. With proper attention
to these details, a perennial garden can provide color and interest
in the landscape throughout the growing season.
Site Analysis
Do a site analysis before purchasing or planting any perennials. Notes
should be taken on soil type, exposure and the amount of sunlight, shade
and wind that each perennial bed will receive. Most flowering perennials
prefer six to eight hours of sun per day. Several perennials are adaptable
to different situations, although certain conditions like heavy shade
and wet soils will reduce plant selection. It is important all site
conditions are known and that adaptable plant material is used.
Soil Preparation
Soil quality is probably the most important factor in determining the
success of a perennial flower planting. Adequate soil moisture is needed
during the growing season but it is very important that the soil not
stay excessively moist during the winter dormant season. To improve
waterlogged soils, add drainage tile, raise the bed or incorporate organic
matter such as compost or peat moss. Most perennials grow best in slightly
acidic soils (pH 6.5 to 7.0). A soil test can be made to determine soil
pH. Soil amendments should be added and worked in to a minimum depth
of 6-10 inches prior to planting.
Selecting Plants and Planting
Selecting Plants. Perennial flowers are sold both in containers
and bare-root. Plants should be healthy and show no signs of disease
or nutrient deficiency. Container grown plants should be removed from
the container to examine the roots. Healthy roots should be white and
be able to hold soil. Do not buy plants with dark colored and/or tightly
coiled roots. Bare-root plants should be checked to ensure roots have
not dried out and that the young shoots are not wilting.
Container Plants. Generally, container-grown plants can be planted
throughout the season. Most often they are planted in the spring. Perennials
that are grown in the greenhouse should not be planted until after danger
of frost (32ºF) has past, much like annual bedding plants and vegetable
transplants. Container-grown plants that have been exposed to outside
temperatures throughout the winter can be planted as soon as the soil
can be worked, about the same time trees and shrubs are planted. Fall
planting of perennials promotes development of roots before onset of
winter.
Bare-root plants. To avoid drying out, perennials bought bare-root
should be planted as soon as possible. Roots should be spread out and
soil placed and firmed between them when planting.
Planting depth. A majority of perennials should be planted out at the
same soil level as they were in their containers or grown at (bare-root
plants).
Routine Maintenance
Once established, most perennial flowers require only routine maintenance.
Watering, fertilizing and mulching are essential maintenance practices
that help perennials perform at their best. Thinning, pinching and deadheading
are maintenance practices that promote longer bloom periods.
Watering. Although water requirements of perennials can vary greatly
from species to species, most require supplemental watering until well
established. One inch of water a week is suitable for plant establishment.
Once established, many perennials will require watering only during
prolonged dry periods. Select waterwise perennials to reduce the need
for supplemental watering. Watering should be deep, infrequent and applied
directly to the soil. This type of watering will promote deep rooting
and will help reduce leaf diseases.
Fertilizing. With proper soil preparation and improvement before planting,
most perennials require little additional fertilization. Application
of a 'starter' fertilizer when perennials are first planted may aid
in more rapid establishment of the root system. For established plants,
an annual application of a balanced, slow release fertilizer can be
beneficial. Fertilizers high in nitrogen should not be used as nitrogen
promotes excessive foliage production at the expense of producing flowers
and a strong root system. Apply fertilizer so it does not come in contact
with the leaves, as it may scorch them.
Staking. Exposure to wind varies with the site. Thought should be given
to staking, particularly if growing taller perennials such as delphinium
or lilies on windy sites. It is best to stake plants when they are first
sending growth up because smaller plants are easier to work with and
less likely to be damaged by staking. Staking early is also more aesthetically
pleasing because new plant growth will cover the stakes. A stake two-thirds
as high as the stem's mature height should be pushed into the ground
near the base of the shoot. Be careful not to harm the plant's roots.
Secure the shoot to the stake using twine.
Mulching. Mulch applied around perennials will help suppress weeds
and improve soil structure while conserving soil moisture. Apply approximately
2 inches of a coarse mulch around the perennials, being careful not
to apply too much around the crown of the plant. Excess mulch around
the crown may hold moisture in and result in increased disease problems.
Weeding. Hand weeding reduces competition for water and soil nutrients.
If herbicides are used, do so carefully, as not to harm the perennial
flowers.
Flowering. Thinning dead and damaged shoots during the early stages
of growth encourages stronger and healthier shoots. In late spring or
early summer, when the plant is about one-third of its mature height,
pinching can be done to increase flower development and encourage side
shoot development. Pinching back new growth will help produce bushier
plants which are less likely to require staking. Unless seedheads are
used for winter decoration or seed is to be collected from them, flowers
should be removed when they begin to fade. Deadheading may also promote
additional flowering.
Fall Cleanup. Once perennial plants have finished growing in the fall,
cut the shoots down to the base (or leave 2 - 6 inches) and remove the
debris. For plants that have some winter aesthetic value, like Sedum
sp., cleanup can be left until spring.
Winter Protection. Perennials damaged or killed during the winter usually
are not injured directly by cold temperatures, but rather by rapidly
fluctuating soil temperatures known as frost heaving. Frost heaving
occurs when the soil alternately freezes and thaws, resulting in damage
to the dormant crown and root system. Mulching in late fall with woodchips,
pine needles, clean straw or other loose materials will help stop frost
heaving. Do not use tree leaves or grass clippings as they may compact
around the plant. Winter mulches should be applied after the ground
freezes, usually in late November, and removed in early to mid-March.
Dividing
Most perennials can be divided, and in fact need periodic division to
maintain vigor and maximum flower production. This may need to be done
annually, as with hardy chrysanthemums, but is usually only necessary
every three to four years. Some perennials, such as baby's breath (Gypsophila
paniculata), never should be divided.
Timing. The time of year when perennials are divided is a major factor
in determining their success. Species that bloom from mid-summer to
fall, are best divided in early spring, before new growth has begun.
Perennials that bloom in the spring to early summer should be divided
in the fall, or after the foliage dies. Exceptions are iris and daylilies,
which are divided immediately after flowering.
Preparation. To divide a perennial, first remove the plant from the
ground by digging around and under the entire plant and lifting it carefully
from the soil avoiding root damage. Shake loose soil off the roots gently.
Remove and discard diseased parts and cut back the top of the plant
(stems, shoots, leaves) to about 6 inches.
Dividing. Fibrous rooted plants often can be divided by hand or by
using two forks back-to-back. Divisions usually are taken from the outer
perimeter of the plant, as this younger area tends to produce more healthy
and vigorous growth. Plants forming a woody center or that have solid
roots can be divided by using a sharp knife or a spade to cut through
the crown. Divide the plant in such a way that each new division has
at least three buds that will produce new shots.
Replanting. Replant new divisions as soon as possible. Rework the soil
if necessary to improve drainage and structure. Dig a hole of adequate
size, allowing room to spread out the root system of the division when
planting. Take care to replant the division at the proper depth. Water
well and protect the plant from the sun on bright, warm days. A winter
mulch is needed for divisions that are replanted in late summer or fall
to help prevent frost heaving.
Insects and Disease
If the perennials are not growing well, in spite of using adaptable
species and planting in suitable locations, check for insects and diseases.
Thrips and aphids are common insects affecting plant growth. Mildews,
leaf spots, molds, rust and viruses are common diseases that may infect
perennial plants. To help prevent insect and disease problems, all debris
should be removed from the garden and clean tools should be used.
This information provided by the Nebraska Cooperative Extension www.ianr.unl.edu
