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snow on the mountain bishop weed seeds

One of the most difficult things about growing Aegopodium is preventing it from spreading into areas where it isn’t wanted. The plants spread by means of brittle underground rhizomes, and digging up unwanted plants often causes them to spread even more because broken bits of rhizomes quickly form new plants.

In late spring or early summer, the plants produce small, white flowers. Many growers think the flowers detract from the attractive foliage and pick them off as they appear, but removing the flowers isn’t necessary to keep the plants healthy.

Growing Snow on the Mountain Ground Cover

When growing variegated forms of snow on the mountain plant, you may occasionally see a solid green plant. Dig these plants out immediately, getting rid of as much of the rhizomes as you can. Solid forms are much more vigorous than the variegated ones and will soon overtake the area.

To compensate for this, install an edging that sinks a few inches (7.5 cm.) under the soil around the bed to contain the plants. If it spreads beyond the desired area, an herbicide may be the only solution. Snow on the mountain plant only responds to herbicides when there is new growth on the plant, so use it in early spring or mow down the plants and allow new growth to emerge before spraying the plants.

Snow on the mountain plant is hardy in USDA plant hardiness zones 3 through 9. Growing Aegopodium is easy in the right location. It tolerates almost any soil as long as it is well-drained, and needs full or partial shade. Shade is particularly important in areas with hot summers. In locations with mild summer temperatures, snow on the mountain ground cover won’t mind some morning sun.

Aegopodium podagraria is a member of the familiar Apiaceae or Parsley family. Flowering plants in sunny sites may reach a height of about 70 cm, but on woodland sites the plants are mostly 20-30 cm tall, with alternate, compound leaves with sheathing bases. Not all plants have the distinctive white borders shown above.

Aegopodium podagraria is widely planted in yards. It is not yet a major invasive species in Wisconsin and it may never be, but it has the potential to persist for long periods where it has been planted or discarded and to spread into adjacent woodlands. It is known to be very difficult to remove once established and it seems better to be cautious with this species. There is no question that when it is well established it is very aggressive and can crowd out a large proportion of the native species that would otherwise grow there. It does not appear to produce viable seed, so spread is primarily or entirely by vegetative means. It is very easy to recognize, so the best plan is to find new sites quickly and destroy the plants. Attempts to control it by pulling or even digging the plants have been largely unsuccessful unless all the rhizomes are removed. The recommended control is to use an herbicide on young leaves, as mature leaves are very resistant. Follow-up will probably be required.

Invasive Plants of Wisconsin

This species is much more widely spread than the map indicates. The record of distribution of plants in Wisconsin depends on the (mostly voluntary) collection of vouchers sent to state herbaria.