Snow-on-the-Mountain

Rob writes~ We have about a 8' x 16' landscaped area in the front of our house. This area contains various shrubs and grasses and is covered with mulch. Unfortunately the previous home owners planted some "snow on the mountain" which has taken over in this area. Every year, we try and pull it all out but invariably we miss some and it comes back stronger than ever. I'm afraid to hit it with week killer because I can't find the direct root and I may wind up hurting the other plants. Any thoughts on how we can permanently get rid of this plant?

A. You are so right about its evasive properties. Once established, it is almost impossible to get rid of. It becomes a true weed. You must dig up each plant all season long and prevent any from flowering, as the seed is what overwinters if you have cold winters [you did not state where you live]. Otherwise it will come up again and again from its roots system.

I can only state that you have to be diligent and weed it out every 3-4 days. Any lapse and its hold will be strengthened if no plants are ever allowed above ground, it will die due to lack of food and seeds will not be produced. Unless you can dig out your desired plants, you must weed around them. The alternative is to dig out what you desire, plant them elsewhere and treat the entire mess with Roundup or a similar weed killer product. The following season, you can check for any hangers-on and replant with what you desire.

SNOW-ON-THE-MOUNTAIN [Euphorbia marginata] is a common garden ornamental. Ingestion causes intense burning of the mouth, throat & stomach, uncontrollable salivation, and sometimes more serious symptoms. Some people find casual handling causes skin irritation as well. It's not a bad idea to wear gloves when tending these plants in the garden. This plant emits a milky fluid that is poisonous, causing an inflammation of the skin similar to that seen with poison ivy.

It is a Hardy Annual. Zones 1-11. Grown for its striking foliage and mostly white flower bracts. Used to cover dry banks and other difficult areas, mixed bed, borders or the cutting bed. This hardy plant may also be used as a groundcover and will block out weeds with its vigorous growth. Tolerates a wide range of soil conditions from rich to poor, moist to dry, baking sun or light shade.

http://www.dulley.com/plant/a047.shtml

Judy writes~
I have had "snow-in-the-mountains" planted on north side of house for about 10 years. They were doing great! Then the last few years some of them are turning solid green. This year about 1/2 of them are the solid green. I would like to know what I can do to get them all back to having "snow-in-the mountain."

A. Snow-on-the-Mountain is the common name for Euphorbia marginata. This is a tender annual that grows into a 2-3' bush, but reseeds year after year in many areas. Its silvery solid green foliage produce clusters of tiny white flowers. An easy way to tell what you have is by breaking off a stem. Snow-on-the-mountain will have a milky sap, similar to milkweed. Wear gloves when you do this as the sap is a skin irritant. To regain the variegation, switch to a fertilizer high in the middle number of the three, Phosphorus. High in the first number, Nitrogen, leads to solid green foliage. Look for an acidic formula which will lower the soil pH. Propagate the variegated stems, plant amongst the desired plants and remove many solid green plants and discard. Also...Aegopodium podagraria 'variegatum' is the common name Bishop's-weed, a perennial that has a flower and stem similar to Queen Anne's Lace that grows above the plant. This plant is often misnamed snow-on-the mountain. Bishops weed has a variegated ivy shaped leaf with a pale green center and irregular white margin and grows up to 12" high, anywhere it wants to. It is a weed and invasive. Its removal requires getting every piece of root, best done by spade removing a clump onto a piece of plastic and handpicking until no more white root is seen. If you use a shovel or try to hand weed, roots break of and regrow.