Cagwin & Dorward Landscape Contractors

Thousands of California workers seek medical treatment for
poison oak dermatitis every year. While some individuals are less susceptible than others, no one is completely immune. There are some simple things you can do to prevent or minimize the unpleasant often-disabling effects of poison oak exposure. You need to recognize, avoid, and prevent exposure, and get rid of it when possible.

BIOLOGY

Recognize the poison oak leaf looks like a miniature oak
leaf, a triple leaf pattern leading off one stem with prominent veins and a shiny surface. In some regions the leaves remain green during the entire time they are on the stem. In other areas the leaves change to various colors with the changing seasons. After the leaves fall off, the bare wood is also dangerous and so are the roots.

It can grow in the form of vines, trailing shrubs, or upright woody shrubs. It may flourish in the deep woods where soil moisture is plentiful or it may be found in very dry soil on the most exposed hillsides.

Stay away from any vegetation that you suspect may be poison oak. Avoid contact with anything that touched it, whether animal, clothing or tools.

Sometimes you have to enter or work in areas where there is poison oak. When this is necessary, certain precautions can be taken:

Wear protective clothing such as long-sleeved shirts, long pants tied around the ankles, leather gloves with gauntlets and neckerchiefs.
Several protective creams are available which form barriers to protect against the toxic oil found in all parts of the plant.
There are also injections or tablets that provide protection for some people.
When removing clothing, takes shoes off first and leave them outside for decontamination by washing.
Remove all clothing and wash it separately.
Any object you touch after having been exposed to poison oak can act as a carrier to contaminate others.
If you come in contact with poison oak, wash immediately or take a shower, not a bath, using strong soap or detergent.
When dressing, put shoes on last so that any poisonous substance remaining on shoes does not contaminate the inside of your pants.
For severe inflammation and itching, consult a physician.

CONTROL

No part of the plant should ever be eaten. It is violent irritant and poisonous. It should never be destroyed by burning. Inhalation of the smoke can be very dangerous. Destroy poison oak by using an approved vegetation spray to eradicate it: Below are listed some popular herbicides. As with any pesticide,always READ THE LABEL AND FOLLOW ALL DIRECTIONS AS TO SAFETY AND USE:

Herbicides used to control poison oak in California include:

Glyphosate ( Round-up Pro )
Auxinic herbicides Triclopyr ( Garlon, Ortho Brush-B-Gon)
2,4-D (Spurge & Oxalis Killer)
Dicamba (Banvel, Spurge & Oxalis Killer)

These herbicides can be applied as stump or basal
applications, or as a foliar spray.

Glyphosate is one of the most effective herbicides for
control of poison oak. Effective control depends on proper timing of the applications. Apply glyphosate late in the growth cycle, after the fruit have formed but before the leaves lose their green color. A 2% solution in a back-pack sprayer works well.

Auxinic herbicides, such as Triclopyr, 2,4-D, dicamba, and
combinations of these are also used on poison oak. The application timing with auxinic is different than for glyphosate: applications can be made earlier, when the plants are growing rapidly from spring to midsummer. Triclopyr is the most effective. It has a wider treatment
window and gives a more consistent control. There are two formulations available, an amine and an ester.

When 2,4D is combined with dicamba, it provides much better control than if it is used alone in a 1% solution. Premixed combinations of these herbicides are available. Dicamba applied at 1/2 % gives better long-term control of poison oak than just 2,4D alone.

The newest herbicide in California is Imazapyr. It is to be
applied by licensed applicators only. There are two
formulations. The water soluble (Arsenal) is applied foliar with a 1% solution plus a 1/4 % surfactant. A similar treatment with ( Stalker, Chopper) will control poison oak with a 2% solution in water, or a 1% solution plus 5% of a methylated or ethylated seed oil. The best time is
either in spring after full leaf expansion or in later summer mid-August through September.

The following are the 3 application methods used today.

STUMP APPLICATION

Stump application are most effective during active growth. Cut stem, 1 to 2 inches above the soil surface and immediately after cutting, treat the stump. Do not delay, this will result in poor control. You can use a paint brush or a squeeze bottle. See label for chemical rates. Be sure to completely cover all surfaces, until it runs down the base of the stubs. Spray any regrowth from cut stumps with a foliar spray when leaves are fully expanded.

BASAL APPLICATION

Application can be made almost any time of the year, even
after the leaves have dicolored or dropped. Apply Triclopyr to basal regions with a backpack sprayer using a solid cone, flat fan or a straight stream nozzle. Thoroughly cover a 6-12 inch basal section of the stem, but not to the point of runoff.

FOLIAR APPLICATION

The foliar application is most effective after leaves are
fully developed and the plant is growing actively. The flowering stage is the optimum time to spray. Do not apply any herbicide before plants begin growth in spring or after the leaves have begun to turn yellow or red in later summer or fall. Please remember that 1 application will not
completely control poison oak. You must re-treat new, sprouting leaves when they are fully expanded, this is generally when the plants are about 2 feet tall. Keep on eye on treated areas closely for at least a period of 1 year and re-treat as needed.

Garden -

Garden - Poison Oak

BIOLOGY

CONTROL

STUMP APPLICATION

BASAL APPLICATION

FOLIAR APPLICATION