Plant Answers

Weekly Express-News Article
By Calvin R. Finch, PhD, SAWS Water Resources Director, and Horticulturist
Saturday, September 15, 2007

“Wildflowers”

Most of our wildflowers bloom in the spring, but now is the time to plant their seed. Wildflowers do not require much work, but if they are going to germinate and bloom, certain conditions for a site are required.

• Wildflower seed must reach the soil and not be covered by organic material. That means the best sites have sparse weed cover, and definitely, are not covered by sod.

• Most wildflowers require full sun. They will not bloom in a shady situation.

• Wildflowers will grow in good soil, but do not require it. A rocky thin soil is often the best wildflower planting choice because it is well drained and most other plants do not prosper in such a setting. If the vacant lot or field you are considering dries out every autumn to the extent that you can see bare soil, it is probably a good wildflower plot.

• You can reduce weed cover prior to planting the seed by mowing very low or discing, but if that treatment is necessary it does not bode well for natural reseeding. The thick weeds will probably be back the next year and the seed dropped by your planted wildflowers will not find the soil contact and light penetration conditions that are required.

Wildflowers can actually be planted in rows in plowed and enriched soils, but that really doesn’t make much sense to me. Wildflowers are interesting, tough, and can make an impact when they bloom in masses over a large area, but their blooms are not as showy as domesticated flowers. If you are going to prepare the soil to the degree required by snapdragons and stocks, you may as well grow snapdragons and stocks.

If you select the right site, all it takes is spreading the seed by hand broadcast. A pre and/or post shallow raking increases the germination success, but is not necessary. The seed should not be covered with soil.

The spring blooming wildflowers germinate in the autumn and develop root systems all winter so they can grow quickly and bloom in the spring. Irrigation is not necessary, but the amount of rain helps determine the timing and volume of bloom. A good soaking rain or two, right after the seed is spread and then a good rain in February is usually all that is required. In fact, too much rain can be a problem and result in fewer plants and competing weeds.

There are a number of ways to obtain your wildflower seeds. Many area nurseries sell packets of Texas wildflower mix which includes verbena, bluebonnet, coreopsis, poppies, firewheel, Mexican hat, larkspur, purple coneflower, and other species.

You can also purchase wildflower seeds on the internet. There are several Texas growers that are very reliable.

Bluebonnets are the Texas state flower and by far the most popular wildflower. They bloom in several shades of blue and white, pink, maroon, and “almost red.” Bluebonnets begin blooming in mid-March and often bloom through April. The seeds you buy retail are usually scarified with acid to increase germination.

Coreopsis is also called tickseed. The blooms are yellow, silver dollar size, and daisy-like. They are more tolerant of wet springs than bluebonnets. Most years, they bloom after bluebonnets. On sites they favor they will cover the ground 12 inches deep with a carpet of bloom. Butterflies are especially fond of coreopsis.

Firewheel also has a daisy-like bloom, but the flower has a rust-red on the petals in addition to a yellow ring. Firewheel and Mexican hat, another daisy-like rust colored bloom are the wildflowers that seem to be the most tolerant of dry conditions in mixed seed packets. They bloom after coreopsis and bluebonnets.

Prairie verbena has a blue lavender bloom that is very attractive to butterflies. This flower often begins to bloom earliest of the wildflowers and lingers after the others have quit blooming. It does not usually dominate a field, like bluebonnet, coreopsis or firewheel may.

Larkspurs are not a native wildflower, but they naturalize well in more fertile situations. The plants reach 18 inches tall on most sites and bloom in blue, purple, pink, and white. Larkspurs are a favorite hummingbird nectar source.

Purple coneflower is a perennial wildflower. It is included in every wildflower mix. The flowers are large with a brown center and lavender petals. They bloom in late spring then often again in autumn.

Salvia coccinea is usually the only wildflower included in the Texas mix that blooms in sun or shade. The plant has red tubular flowers on stalks that reach 18 inches tall. It is the latest bloomer in the mix, starting in mid-summer and blooming through late fall. Hummingbirds like Salvia coccinea.