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Dalmatian Toadflax

Scientific Name:Linaria dalmatica

Family: Scrophulariaceae (Figwort Family)

Other common names: Broadleaf Toadflax

Life-Cycle: Perennial that reproduces by seed and rhizomatous roots




Dalmatian Toadflax Quick Guide

Description
Bloom
(varies by elevation)

What to Do

When?

Invades Undisturbed Land
State Class

2-3' stalks of yellow flowers atop clasping waxy blue-green leaves; stalks often form clumps, spreading via roots and seeds.

Bright yellow flowers, easily mistaken as snapdragons, about an inch long, with a little orange on top and a large spur on the end.
Hand pull seedlings and small populations; cultivate farmland repeated; get biocontrols for large groups
May through August
Yes.  Prefers dry, rocky soil, and is most common along roads and old disturbed sites but easily invades all sorts of pristine habitats.

B
young toadflax plant
toadflax covered hillside

General Description
. Don't be fooled by this attractive yellow snapdragon-type flower. Dalmatian toadflax will totally displace almost all other vegetation in the vicinity (including knapweed) if not given your immediate attention! This beautiful beast invades roadsides and degraded rangeland primarily, but also scatters throughout native shrub steppe and riparian areas with ease.
. This aggressive but short-lived herbaceous perennial grows 2-3 feet tall on strong, straight stems, often branching at the top. It can easily be mistaken for a snapdragon with its bright yellow flowers that grow in a head at the end of the main stem.
. The flowers are about an inch long, with two lips, one with a dab of orange, and a noticeable "spur" shooting down from the bottom of the flower.
. Heart-shaped, gray-green leaves "cup" the length of the stem, and get progressively smaller as they go up.

Life-Cycle
. It reproduces both by seeds and by spreading rhizomatous roots. A mature Dalmatian toadflax plant produces up to 500,000 viable seeds per year.
. Seed dispersal begins a few weeks after flowering. They spread by wind and animals (birds and deer) and can remain dormant in the soil for up to 10 years.
. This plant has deep tap roots and extensive lateral roots, and is capable of forming colonies through buds from creeping root systems. It will aggressively colonize disturbed or cultivated ground and out-compete desirable native plant species.
. Young plants have thin, shallow roots that are easy to pull-out in their entirety.

Prevention & Control

    Prevent
    . Eradicate new plants early and aggressively by hand-pulling them several times a year.
    . Screen irrigation water before it enters a field or your irrigation pipes.

    Hand-Pull
    Hand-pulling is the easiest method to eradicate and manage small or sporadic patches as the roots are shallow and the plant grows from seed (not roots). Hand-pulling should be done several times from spring to late summer every year for several years to fully eradicate a patch.

    Biocontrols
    . The stem-boring weevil, Mecinus janthinus, is a tiny beetle that is effective at reducing large Dalmatian toadflax infestations. The larvae mine tunnels inside the stems, causing premature wilting and death of the plant. Weaken or dying toadflax can be out-competed by native plants.
    . The "Regional Biocontrol Project," run through the Ferry County Extension office for both Okanogan and Ferry Counties, is the source of several free biocontrols, including the toadflax stem-boring weevil. Contact Dale Whaley at 509-745-8531 or go to the website.

    Chemical

    Several herbicides are effective at reducing toadflax populations, either by spot or broadcast spraying, both early in the spring and in the fall. A surfactant must be used with the herbicide because of the smooth, waxy surface of the plant. Contact the Okanogan County Weed Board for recommendations.

    See the Herbicide section of the "Toolbox of Weed Control Methods" for more details on spraying.

Interesting Tidbits
. Its name is derived from the Dalmatian Coast of the Adriatic Sea located within its native range.
. This species has escaped cultivation as an ornamental garden plant, a source of fabric dye, and as a medicinal plant to become an invasive weed.
. Yellow toadflax (Linaria vulgaris) is a different but very similar looking plant. It is a Class A weed in Okanogan County, meaning eradication is required by law. It is not common, so the County wants to keep new populations from spreading. One of the main ways to tell them apart is by their distinctly different leaves. Dalmatian toadflax leaves are heart-shaped and clasp the stem, while the leaves of yellow toadflax are long, narrow, and pointed at both ends.

Resources & Photos
* Okanogan County Noxious Weed Control Board

* Biocontrols for Dalmation Toadflax fact sheet from Lincoln Co., WA

* More Images: http://biology.burke.washington.edu/herbarium/imagecollection/taxon.php?ID=5053

 

 
 
 
 
 
 
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