Aegopodium

( ee - go - POH - dee - um )

At-A-Glance Information

These groundcover plants are native to Europe through western Asia, and are commonly called Bishop's Weed, Ground Elder, Snow on the Mountain or Gout Weed. These are perennials that enjoy both sun and shade and need moderate water to perform well in the landscape. Light green leaves create a spreading carpet 6-12 inches tall, and flat-topped clusters of white flowers bloom above the foliage in spring and summer. Flowers will attract pollinators to the garden. Even in mild-winter areas, these plants are considered deciduous. Use Aegopodium as groundcover, as an underplanting for trees, or in containers. Take care when planting this groundcover in the garden, as they are toxic to animals if ingested. This groundcover is also considered to be invasive in many areas of North America, so check with local authorities before planting.

Aegopodium Species and Varietals

The genus Aegopodium is a member of the plant family Apiaceae and includes 12 distinct species, only one of which is commonly grown as a garden ornamental (Aegopodium podragraria). Bishop's Weed grows best in USDA hardiness zones 3-9 and Sunset zones A1-A3, 1-9, 12, and 14-24. To find your zone, click here: Zone Map.

Aegopodium podagraria (Ground Elder, Herb Gerard, Bishop's Weed, Goutweed, Gout Wort, Snow-In-The-Mountain, English Masterwort, Wild Masterwort)
This species produces green leaves, and should be set in the ground about a foot apart for best groundcover coverage. In warm climates, locate this plant where it will get some shade during the warmest hours of the day. Cultivar 'Variegatum' (pictured) has green leaflets that are edged in white.

Caring for Aegopodium

Plant Aegopodium in a space in the garden that receives partial to full shade and can accommodate a spreading plant. Bishop's Weed can handle non-irrigated areas of the landscape well, and are a perfect choice for shaded urban situations where few other plants will grow and its spread is controlled by sidewalks or roadways. These plants easily outcompete others for nutrients and water resources, and so they should not be planted close to any valued plants. Install plants 12-24 inches apart for best coverage and airflow. They can thrive in any type of soil, as long as it is well-draining. If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing for best results. Water new plantings regularly as they establish a strong root system in their new home. At maturity, Bishop's Weed can handle very dry conditions, as long as it is grown in shade. The more sun these plants get, the more water they will require in order to stay healthy.

Do not fertilize these plants. Pruning is simple; remove any damaged, diseased, or dead foliage at any time during the growing season, and remove spent flower spikes to neaten up the appearance of plants and encourage reblooms. If you do not want Bishop's Weed to spread through the landscape, make sure to take off flowering stems before they set seed. Aegopodium plants can be mowed to the ground in summertime or left to grow wild. If these plants are grown in cramped spaces or in containers, they will need to be divided every so often to ensure ongoing health. The best time to divide Aeogopodium rhizomes is in autumn; for instructions on how to successfully divide Aegopodium plants, see the Propagation section below.

Propagation

Aegopodium, or Bishop's Weed, can be propagated by division or seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the division method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant, especially if you are propagating a hybrid cultivar. To propagate your Bishop's Weed, follow the instructions below:

Propagating Aegopodium by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
Harvest your seeds. The seed heads on plants are pretty easy to spot, they're left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will continue to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
Get your container prepared. Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 2-6 weeks from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 65 and 72 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Propagating Aegopodium by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil (any kind will do, though it does need to be well-draining), compost and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in very early spring (after the plant has entered dormancy, but before it has begun its new spring growth), and needs to be done every few years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:

Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the root(s). Once you have worked it up out of the ground, lay it out.
Start to tease apart the roots with your fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick root section attached.
Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divisions and water thoroughly.
Apply a thick layer of mulch over the new planting to protect it from cold weather as it acclimates to its new home. Then, enjoy watching it sprout in the next growing season.

Problems and Pests

Aegopodium itself is considered to be a pest in many gardens; It spreads rapidly under favorable growing conditions. Because of this tendency, it has been described as a nuisance species, and been labelled one of the worst garden weeds in perennial flower beds. It is also considered an invasive species in some areas of North America, so make sure to check with local authorities before planting.

Aegopodium, or Bishop's Weed, plants can be susceptible to developing issues with the following pests and diseases in the landscape: