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Revised May 2002

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Contents

• Why grow wildflowers?
• Conservation of wildflowers
• Characteristics in landscapes
• Designing the wildflower garden
• Woodland and meadow wildflowers
• Field or meadow wildflower gardens
• Propagating wildflowers
• Suggestions for home gardens
• Explanation of tables

Related publications

• G6902, Low-Maintenance Landscaping
• G6970, Home Propagation of Garden and Landscape Plants
• MG9, Herbaceous Ornamentals

Use our feedback form for questions or comments about G6660.

Wildflowers in the Home Landscape

David Trinklein
Department of Horticulture

The term "wildflower" may seem a contradiction when we use it to describe plants growing in the garden. How can a plant be wild when it is growing in cultivation? Needless to say, the word means different things to different people. All plants we grow were at some time wild somewhere. In modern use, however, a wildflower is a plant that has not undergone any change or improvement by humans and usually is still found growing natively somewhere in the region where it is being cultivated.

The Missouri primrose is a native wildflower well adapted to home landscapes.
 

Why grow wildflowers?

Some people consider wildflowers hardy and durable and believe they can be grown in the garden with little care. This often is the reason given for growing them. For some plants this is true, but others need very specific conditions to grow and thrive. If they are not given these special conditions, they will decline and eventually die.

Many sites in the landscape are too shaded or too extensive for popular garden flowers. Wildflowers often are well adapted to these sites and do not need extensive maintenance if a less "manicured" landscape appearance is acceptable.

Conservation of wildflowers

Wildflowers are found in a wide range of habitats. Those that are rare, threatened or endangered should never be removed from their native habitat. Moreover, it is unlawful to remove any wildflower, endangered or not, from public land. This includes highway right-of-ways. Anyone interested in growing wildflowers should select those that can be grown from seeds or propagated in other ways for use in the garden. Avoid digging from native locations unless native locations are being destroyed for some reason.

There are a number of reputable garden wildflower producers. In addition to mail-order sources, you may have wildflower nurseries near your home. Always check with local nurseries and garden centers to determine whether local sources are available. Some dealers dig plants from the wild and sell directly, or perhaps hold plants that have been dug from the wild for a few months or a year before selling them. For the sake of conservation, plants from seeds or propagated from native stock for many years should be preferred to those that are dug from wild stands. Plants not dug from the wild may cost more, but they will be more successful in the garden and you will not be encouraging depletion of natural stands.

Virginia bluebell graces the spring woodlands with brilliant blue blossoms.
 

Characteristics in landscapes

If you are interested in developing a wildflower area in your landscape, several characteristics of these plants should be considered:

• No plant chosen for the garden should be a noxious weed. Neither should a plant be so aggressive that it will invade other areas or crowd out desirable nearby wildflowers. Plants that are particularly aggressive are noted in the following tables.
• The plant must be either a perennial or an annual that self-seeds in order to maintain itself from year to year. This quality helps eliminate yearly attention to fill bare spaces.
• The plant should have some showy characteristics to make it desirable in the wildflower area. The showy part may be flowers, leaves, stems or seed structures.
• The plant must have a good root system so it can endure dry periods without watering and also help in conserving soil and preventing erosion.
• The plant should not be poisonous to humans or animals.
• The plant must be well adapted to the conditions available. It must be shade tolerant for the woodland garden, sun and drought tolerant for the meadow garden, water tolerant for the bog garden or other special conditions.
• In some conditions, the plant must be able to compete and persist when mixed closely into other vegetation, such as grasses in the case of meadow plants, or trees in the case of woodland plants.

Too much fertilizer to tall wildflowers such as Filipendula and gayfeather can cause stems to fall over.
 

Table 1
Woodland wildflowers suitable for a wildflower garden in a shaded or lightly shaded location.

Table 2
Meadow and field wildflowers suitable for sunny, open locations.

Designing the wildflower garden

Many wildflowers may be used in combination with other perennials or annual flowers in a perennial border. Many people, however, prefer to have an area designed specifically for wildflowers to develop a naturalistic look with relatively low maintenance.

Black-eyed susan is an excellent choice for poor soil and full sun conditions.
 

Mayapple graces the spring woodlands with white blossoms.
 

Goldenrod is attractive to butterflies and, despite popular belief, seldom causes problems with allergies.
 

Helenium, or sneezeweed, warms the late summer garden with its yellow, orange or bronze daisylike blooms.
 

The spreading nature of wild sweet william lends itself well to propagation by division.
 

Jewelweed, found in moist shady sites, is sometimes used to relieve itching.
 

Named cultivars of wildflowers, such as Echinacea purpurea 'Bravado,' must be asexually propagated to maintain the characteristics of the plant.
 

If you have an opportunity to visit native sites or state forests, note the plants that grow there. Compare the sites of plants you prefer to the area or areas in your own landscape. For instance, if your site is wooded and contains a lot of shade, then a woodland wildflower garden may be your only choice (Table 1). If the site is sunny and dry, a meadow, prairie or field collection of plants may be most suitable (Table 2 for a listing of some sunny-site species).

Wildflowers are not tolerant of foot or animal traffic. Paths should be developed so that you or your guests may walk among them, but not on them. They should not be used in areas where animals may frequently run over them. Most wildflowers cannot endure the crushed foliage and soil compaction that can result from such locations.

The actual placement of plants in the design is very flexible. Nature is very random and the wildflower garden should convey this appearance. Clusters, clumps or individual placements are quite useful. Perhaps the only arrangement to be avoided is that of plants in rows or precise geometric forms.

Woodland and meadow wildflowers

Woodland wildflowers have these basic needs:

• Light shade
• Adequate moisture
• Soil high in organic matter
• Well-drained soil
• A leaf mulch or other organic mulch that persists throughout the year.

Meadow or field wildflowers have a different set of needs:

• Full sun for at least 6 to 8 hours daily
• Adequate early-season moisture
• Well-drained soils with average to moderate fertility
• Protection by nearby noninvasive plants rather than mulch, although light mulch can be used. Meadow wildflowers are fairly drought tolerant in the late season and are weakened by overfertilization.

Shade
Most woodland wildflowers do not grow in dense shade. They are at their most attractive in light shade, which in nature tends to be near the edge of the forest or under tall trees with high branching. The more limited the moisture supply, the more important is the shade during the heat of the day for good growth and survival. Some woodland wildflowers that flower in early spring become dormant by midsummer and will not be seen again until next season. These often grow before a dense canopy of leaves develops and can be used in more heavily shaded locations.

Moisture
Many native wildflowers are able to sustain considerable drying. However, others such as trillium, jack-in-the-pulpit and mayapple will grow and develop best where there is adequate moisture, particularly while they are growing rapidly or flowering. These plants also will go dormant in midsummer when dry conditions develop. Tree roots can be very competitive for moisture, so be prepared to give them some additional moisture, particularly during establishment or drought periods.

Most meadow wildflowers listed in Table 2 are for the dry field or meadow. However, a few of those listed are suitable for the low, wet area. These are noted in the table and are by no means the only ones that might be used.

Soil
Wildflowers are adapted to certain native soils and normally can endure in conditions similar to the ones in which they grow in the wild. In the case of woodland wildflowers, organic matter is quite important. They normally grow in locations where leaves and other plant debris accumulates and becomes a part of their soil environment and a mulch. Organic matter helps hold moisture and helps soil stay loose and well-aerated. Liberal amounts of organic matter should be added to prepare woodland wildflower gardens. Leaf compost is particularly suitable.

Most woodland wildflowers need well-drained soil, but there are those that grow along creeks in wooded areas that tolerate or may need wetter conditions. Cardinal flower, jewelweed and forget-me-not are prime examples of this group, but it is best to know individual plant needs to fit them into the proper soil moisture requirement. The tables briefly indicate whether a plant needs wet, moist or relatively dry conditions to survive best.

Acidity
Wildflowers that thrive in Missouri generally can be expected to need soil that is somewhat acid. Most plants listed will grow best in a pH range from about 5.5 to 6.2. However, most wildflowers are adaptable and are tolerant of an even wider pH range. It usually is not necessary to lime soils that are to be used for wildflowers unless the native soil is unusually acid. A soil test to determine existing soil conditions is important in starting wildflowers in a new location where wildflowers may not have been grown previously.

Mulch
Woodland wildflowers should not be grown in bare soil as is often done with popular garden flowers. They need a mulch or the protection of another low-growing, noncompetitive plant nearby. Mulches keep soil cooler, maintain more uniform moisture and aid in winter protection. Oak leaves are a very durable and suitable mulch for many of them, although most woodland wildflowers will benefit from a mulch of any type of leaf cover.

A mulch is less necessary for meadow or field wildflowers. However, they benefit from the protection of nearby low-growing plants. In Table 2, mulches are mentioned primarily for winter protection of species more suitable to warmer portions of the state.

Purple coneflower, or Echinacea, is a durable, drought-resistant wildflower that enjoys great popularity for both its ornamental and its medicinal properties.
 

Field or meadow wildflower gardens

The field or meadow wildflower garden is different from woodland wildflower gardens. It is composed of a wide range of plants that flower in full sun or must have at least 6 hours of full sun each day to grow and flower well. Soils for these plants generally can be less fertile and lower in organic matter. Field wildflowers may grow better in better soils, but they also are more tolerant of poor growing conditions.

Another characteristic of this group of plants is that many can be easily seed propagated or sown directly. The most commonly available wildflower seed mixes generally are intended for this type of wildflower garden.

While the meadow wildflower garden may be grown from divisions of larger plants, the seeding method should not be overlooked, particularly if larger areas are to be covered economically. Although seeds of meadow wildflowers may be planted at any time, August and September are very favorable. Many weed seeds will not germinate in fall while the wildflowers will germinate and get a head start on the spring weeds. Some require chilling conditions before germination, but will receive this during the winter and germinate early next spring.

Since deep cultivation tends to bring up more weed seeds, it is not essential for planting wildflowers unless the soil has been extremely compacted. After a sunny area has been selected, rake the area with a garden rake or other equipment to loosen only the surface. This need be no more than about 1/2 inch deep. Broadcast the seeds or wildflower mix over the prepared area. After seeding, lightly rake over the area to establish good contact between the seeds and the soil. Water the area lightly to settle the soil and begin the germination process.

If the area selected already has perennial grasses and broadleaved weeds on it, the weeds should be pulled out or killed before seeding. Weeds can be killed by spot treating with a glyphosate herbicide (Roundup). The grass also may be killed at that time or left in place on slopes or areas where wildflowers are wanted, but erosion may occur if the grass is eliminated.

Some field wildflowers can exist in combination with grasses. They should not be planted with grasses that grow aggressively during cool fall and spring weather, such as fescue and rye grass. These vigorous cool-season grasses will crowd out the small wildflower seedlings during this period when they will grow very little. If this is to be done, mow the vegetation as short as possible. Remove the clippings and rough up the surface with a stiff rake, hoe, dethatcher, or other equipment. Broadcast the seeds over the area, rake them in, and water lightly.

These types of wildflower seeds should begin germination in two to three weeks after planting. Maintain frequent light watering during the germination period to keep the soil surface moist but not overly wet if natural rainfall is inadequate.

Meadow wildflowers are of two types: those that are perennial and return each year from the same plants and those that are annuals, but reseed readily each year. Those that reseed must be allowed to finish flowering and develop fully matured seeds before they are cut down in summer or fall.

In the spring after wildflower seedlings have become established, a preemergence herbicide might be used to reduce the development of annual grasses such as crabgrass in the area. This is most critical during the first season, but is less essential as the wildflowers become well established and soil is not disturbed.

Propagating wildflowers

Collecting native plant seeds. When a sizable group of wildflowers is found, selective collection of seeds will have little or no effect on the reproduction of the area. Once established, you will be able to get additional seeds from your own plants. Seed collection can become an interesting hobby. It may be necessary to keep a careful eye on developing seeds, to pick them after seed heads begin to brown but before seeds drop out. Wildflowers may be very obvious in bloom, but often become hard to find by the time that seeds are mature, so some advance scouting and marking may be necessary. Seed stalks are best left on the plants for at least a month after flowering, but may take longer.

After collecting seed structures, open them to examine seeds contained. There are many different forms and sizes of seeds, but they generally should be fairly plump and firm if they are viable. Some plants may not produce seeds if conditions have not been favorable during the pollination or development stages.

Many wildflower seeds have a dormant period and will not germinate immediately. However, if planted promptly after harvest, this dormancy may not develop and rapid germination will occur. In the tables where midsummer or early fall planting is suggested, this really means prompt planting after harvest of the seeds.

If dormancy is natural or does develop, this means that some type of chilling will be required before the germination can be completed. Summer or fall planting is one way to fulfill these needs easily. If chilling is required, those seeds that need it will not germinate in fall, but will germinate early in spring.

Some seeds have a hard seed coat that must break down naturally in the soil before germination can occur. With these types of seeds, a process called scarification can be done to speed germination. Very hard seed coats often are found in plants of the legume family and can be bypassed by filing a small area on individual seeds, cutting a nick into the coat with a knife, or treating with acid. There are many techniques that can be used, but nature will do the job if given time.

Asexual propagation
Any type of plant increase that does not involve seeds is known as asexual propagation. Several methods are suitable to wildflowers, depending on the plant involved.

Division
This technique is probably the most suitable and easiest method for multiplying many wildflowers. It should not be done when the plants are in flower, but when they are dormant and not actively growing. Many of the spring-blooming woodland wildflowers should be divided in the fall as growth ceases, or at that time of year when the natural growth is yellowing and collapsing.

Do not divide plants more than necessary to multiply them and keep them healthy. At the proper time, carefully lift the clump from the garden with a spade. Remove excess soil and trim back any dead top growth. Some plants that produce multiple offsets in the crown such as black-eyed-susan can be divided by pulling them apart. Woodier plants may have to be cut apart with a knife or pruning shears. After division, the smaller plants should be replanted immediately at the same depth at which they were previously growing.

• Root cuttings
  This is a technique suitable for a few wildflowers with fleshy roots. Butterfly weed is one that can be multiplied by this technique.
  In most plants, root cuttings should be made in early spring before topgrowth begins. Remove some of the largest roots from a clump. Ideally in most plants the roots should be thick, at least the diameter of a pencil. Cut them into pieces about 3 inches in length. Plant them in a pot, flat or coldframe either horizontally or in the same position they were growing. Do not plant them upside down. The top should be at soil level with the root preferably in a vertical position. A mixture of half sand and half peatmoss works well for many plants.
  In several weeks, shoots should develop from the roots. Do not be in a rush to move them into the garden. Let them get well developed.
• Stem cuttings
  This type of propagation is used less for wildflowers than for many other plants. However, it is still useful in some cases. Generally, young basal shoots make more suitable stem cuttings than older, more mature or flowering stems. The methods for rooting these cuttings are the same as for softwood cuttings of many ornamental plants. Information in this area is limited, so trial and error may be a necessary means for determining possibilities with untested species.

Suggestions for home gardens

Tables 1 and 2 list wildflowers that may be grown in home wildflower gardens. Table 1 lists those suitable for the woodland or lightly shaded locations; Table 2 lists meadow or field wildflowers best suited for full sun. There are many other wildflowers that could be included, but space does not permit. For the most part, those that are easily grown and not invasive have been selected. However, a few that are difficult and some that tend to be aggressive are included for suiting all needs or locations.

Brief information on bloom time, color, height, soil conditions, propagation and special considerations are included. In each table plants are listed alphabetically by common name with scientific name added after the common name.

Common names are variable, so it is possible that you may know a certain plant listed with another name. Also many plants closely related to plants listed may be quite suitable. For instance, purple coneflower is listed, but several other plants known as coneflowers, including gray-head coneflower, pale coneflower, Mexican hat and thin-leaved coneflower (also called brown-eyed-susan), could be used in similar sites. The possibilities for using native plants seem almost endless.

Wildflower seed mixes may contain seeds not found in these tables. These are mainly flowers that can be found growing natively in Missouri. However, those in mixes may also be quite suitable for our location but may not normally be found unless introduced. Use the plants suggested in the tables as a guide to a beginning garden, but do not be limited by it.

Explanation of tables

Bloom time
This is approximate and will vary between different localities. In some cases, where the period is extended, major bloom will be early in the period given with scattered bloom following during the time indicated.

Major color
Note this is "major" color. Other shades and colors may exist, particularly if other species of the same genus are chosen.

Height in inches
This is another very variable character, but an indication is given as a guide to possible placement in the garden. Under very good growing conditions or special situations, heights can vary.

Soil type
This column does not really give soil type as much as conditions necessary within existing soils that are available. Rich indicates a need for high fertility, average indicates most existing soils will suffice, poor indicates tolerance to low fertility or a need to avoid high fertility.

Where humus is listed, plants need a soil fairly high in organic matter. If this does not occur naturally, organic matter should be added at planting time and mulch should be maintained.

Moisture conditions also are indicated in this column. Wet means that it needs standing water or at least can tolerate standing water for part of the time. Moist indicates that plants should not be allowed to become too dry. Dry and well drained means that the plant cannot tolerate periods of standing water or excessive moisture for even short periods of time without some damage.

Comments
Used to add statements for additional information. These include unique plant characteristics, other propagation information, special sites suitable, need for winter mulch, weedy or difficult type of plant as well as other items that might be useful.

G6660, revised May 2002