Plant of the Week
Indian Paintbrush
Latin: Castilleja coccinea
Growing wildflowers along a roadway is a tricky business. Being native
plants, logic tells you it should be easy, but such is hardly the case.
But thanks to Mother Nature and a helping hand of the state highway
department, the Arkansas roadside wildflower flora is colorful, abundant and
becoming more diverse each year. A plant that has gained a foothold along our
interstate system in recent years is Indian Paintbrush, Castilleja coccinea.
Indian Paintbrush is what botanists call a "scroph," a member of the same
family as foxglove and snapdragon. Like foxglove, Indian Paintbrush is a
biennial. The first year it grows as a small rosette inconspicuously nestled
amongst the grass and weeds.
The spring of its second year it shoots skyward on a leafy 18- inch,
unbranched spike topped with an orange or scarlet flowers. After flowering and
subsequent seed set, the original plant dies.
The true flowers are small and inconspicuous with the showy portion hairy,
inch long bracts. The flowers are clustered atop of the slender stem and, if
you’re blessed with a good imagination or have been drinking, look somewhat like
an artist’s paintbrush.
Castilleja coccinea is the most common of the 200 species found in the
Americas, ranging from the New England states to north-central Texas.
What makes Indian Paintbrush noteworthy as a wildflower is that botanists
consider it a hemiparasite. It develops haustoria on its roots, a kind of
coupling that allows it to attach to nearby plants and siphon off mineral
nutrients and water. The literature is full of inconsistencies about exactly
what makes a good host plant for this parasite, for apparently any number of
herbaceous and woody plants will work. Oxeye daisy is a commonly mentioned host
plant with a similar growth habit, blooming time and environmental requirement.
The establishment of sustainable populations of Indian Paintbrush along the
roadways begins with fall planting. The seeds require a two-month cold treatment
to satisfy the dormancy requirement, hence germination usually does not occur
until the soil warms in early spring. If a suitable host plant is nearby, the
plant will affix itself and produce its flowers a year later.
Because erosion control is a paramount concern in roadway construction, grass
cover must be established first. Once the grass is established and erosion
controlled, it becomes more difficult for wildflowers to gain foothold along the
roadside. If the site is moist and sunny and a suitable host plant population
exists, a self-sustaining community of Indian Paintbrush grows.
The Arkansas Department of Transportation maintains a modest wildflower
planting program and tries to manage mowing cycles to assure that wildflower
plantings are allowed to reach a mature stage of seed development before the
mowers move in. Many motorists are apparently unaware of the need for time for
seed crops to mature, for one of the most frequently heard complaints by the
agency is that the roads look shaggy and should be mowed. Communities or
organizations interested in wildflower planting projects can purchase seeds and
the DOT will plant them in appropriate areas.
Growing Indian Paintbrush in the garden is difficult at best. Plants cannot
be transplanted, so they must be seeded where they will be grown. Seeds are
commercially available from wildflower seed producers and from the seed exchange
list of the North American Rock Garden Society.
A couple of Pacific Northwest gardeners tell of growing a dozen or more
species in their gardens, but most who have tried find it difficult to establish
and maintain under cultivation.
By: Gerald Klingaman, retired
Extension Horticulturist
- Ornamentals
Extension News -
May 16, 2003
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