DALMATIAN TOADFLAX — Linaria genistifolia ssp. dalmatica (L.) Marie and Petitmengin

Scrophulariaceae — (Figwort family)

Dalmatian toadflax is an attractive, very serious weed problem in Wyoming.  Leaves are heart shaped and the lobes almost encircle the upright stems, they are light green to grayish and waxy.  The leaves are opposite each other and seem almost in a stacked arrangement. 

The top 6-8 inches of each stem are surrounded with yellow flowers that resemble snapdragons. Since each plant has many stems, and many flowers per stem, one plant can produce hundreds of thousands of seeds each year.  
Toadflax has a deep tap root.  In addition it has a system of horizontal roots that grow just under the soil producing many more plants at the root nodes.

This weed is very hard to control because:  (a) it is waxy and resistant to chemical control, (b) seeds may lay dormant for up to 10 years, (c) it has an extensive root system, (d) it is not grazed by livestock or wildlife, (e) it thrives in poor soil, harsh temperatures, and high elevations.  It is important to eradicate this plant before it has time to multiply. 

The following is courtesy of Weeds of the West:

Dalmatian Toadflax is a perennial, up to three feet tall, reproducing by seed and underground root stalks. The plant has broad, waxy, heart-shaped leaves that are dense and alternate. Flowers are borne in the axils of upper leaves. They are two-lipped, ¾ to 1½ inches long with a long spur, bright yellow with an orange, bearded throat. The fruit consists of a two-celled capsule containing many irregularly angled seeds. Early spring growth of this prolific perennial has waxy leaves with a blue-green color. Leaves individually clasp the stem.

Yellow flowers with long spurs appear at midsummer with plants continuing to flower until early fall. Dalmatian toadflax was introduced from Southeastern Europe, probably as an ornamental. It is aggressive and may be found along roadsides and on rangeland where it becomes a serious problem by crowding out desirable forage.

Growth Habit: Perennial, often over 3` tall, erect.

Leaves: Light green, alternate, broad, heart-shaped, clasping the stem.

Stem: Branching, light green, smooth and leafy.

Flowers: Snapdragon type, bright yellow, tinged with orange, to 1½" long spur, born in upper leaf axils.

Roots: Vigorous, deep and extensive, creeping roots.

Seeds: Numerous, irregularly angled.

Other: Spread by seed and creeping roots.
(Courtesy of Weeds of the West)

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