|Conditions:||Sun to medium shade|
|Seed Banking:||Long term|
Pilea pumila, known as Clearweed, Canadian clearweed, Coolwort, or Richweed is an annual plant native to most of North America east of the Rockies. The plants are generally erect, 10 to 70 cm tall, often occurring in large colonies, and are quite common throughout their range both as a woodland plant and a weed of gardens.
The foliage is opposite, simple with dentate margins, wrinkly (with depressed veins), ovate, and with long petioles. Both the leaves and stems are translucent and bright green, turning bright yellow in autumn. The flowers are small, borne in axillary cymes, unisexual with both genders occurring on the same plant, greenish yellow, and pollinated by wind. Flowers bloom from midsummer through early autumn. Fruits (achenes) are green with purple markings. Roots are fibrous, shallow, and adventitious off the stem in moist areas or when in contact with the soil.
This plant is most often found in rich, moist soils in both sunny and shaded locations.
It is sometimes grown as a ground cover for its attractive foliage, but this should be done with caution as the plant easily gets out of control, and can develops long-lasting seed banks if allowed to go to seed. They do form a heavy canopy, and so will keep other weeds down quite effectively.
It can also be grown as forage for deer and goats.
- Pulling: Should be done as early as possible before the plants develop seeds. The plants pull quite easily, but if they are well established, new plants will germinate within 2-3 weeks, depending on rainfall.
- Contact herbicides (synthetic): Can sometimes be problematic because of the glabrous foliage.
- Disposal: These plants will continue to grow in the compost pile if not completely covered. If flowers are present, they should not be added to cold piles.
- P. D. Strausbaugh and Earl L. Core. Flora of West Virginia. 2nd ed. Seneca Books Inc., 1964. ISBN 0-89092-010-9, pg. 318.
- Ann Fouler Rhoads and Timothy A. Block. The Plants of Pennsylvania. University of Pennsylvania Press, 2000. ISBN 0-8122-3535-5, pg. 694.
- Hortus Third, pg. 873.