Snow On The Mountain (Euphorbia marginata) is a slow growing, self-seeding annual. These plants have been growing in my garden for a number of years, though I’m not entirely certain where they came from! I’ve noticed several wild plots of them in some rural areas nearby, so it’s possible the seeds were carried here by birds.
Euphorbia marginata is one of the later plants to make an appearance in the garden, usually popping up when I’ve given up all hope that they’re going to return. They never seem to come up in the same location from one season to the next. I guess it depends upon which way the wind is blowing when their seeds finally decide to drop! I’ve tried to arrange these photos (these are actually a couple of different plants that I took pictures of last year) in the order of the their growth pattern.
Euphorbia marginata is a succulent plant in the spurge family, of which the Poinsettia (Euphorbia pulcherrima) is also a member.
All parts of Euphorbia marginata are poisonous if ingested. The sap can cause a rash or burns to the skin and eyes comparable to a Latex reaction, as well as blistering of the mouth. Just handling the leaves can cause skin irritation. I’ve never had contact with the sap, and have not experienced any irritation from touching the leaves or flowers, so the plant probably affects different people in different ways.
The foliage of Euphorbia marginata is more eye-catching that its flowers. While the lower leaves of the main stem remain totally green, the leaves at the top of the plant are patterned with white margins and in some cases are almost fully white. The same can be said of the leaves surrounding flowers lower down the main stem. The plants grow to a height of 1½-3 feet and a width of about 12 inches.
In contrast to the vivid quality of the leaves, the flowers are inconspicuous and easy to overlook. The small greenish-white clusters of blossoms seem to get lost in the deep green and white of the surrounding foliage. But if you inspect them closely you’ll find that they’re quite pretty.
Snow On The Mountain blooms from mid-summer through fall. It’s always one of the last flowers standing in my garden.
Seed capsules form as the blooms begin to dry and fall off. They’re a little bigger than a large pin-head and somewhat irregularly round. Each capsule contains three seeds. The capsules remain green for quite a while before slowly browning and falling off.
Euphorbia marginata is very drought tolerant. It will withstand extreme heat with only moderate watering and will grow in complete sun to partial shade.
This plant was first noted by the Lewis and Clark Expedition along the Yellowstone River in Montana. It is a Texas native.
Other common names for Euphorbia marginata are Ghostweed, Kilimanjaro, Snow Top, Summer Icicle, Smoke on the Prairie, Variegated Spurge, Whitemargined Spurge and Mountain Spurge.