Gardening with Gary

Gardening Advice from an Expert

Oxalis (Wood Sorrel)

Q. Is wood sorrel the same thing as oxalis, that shamrock-type ground cover? I would like to try some if they can take a fair amount of sunlight and not too much moisture.

A. Yes, it is an oxalis. The Oxalis montana would not be good for you as it is a woods plant and needs moisture and shade as do several other species, so be careful what you buy. But, I have assembled a few others:

O. violacea is another kind that grows beautifully in the rock or wild garden. It ranges from Massachusetts to Florida and westward to the Rocky Mountains. It will grow 3-6 inches high and bear rosy-purple flowers in the summer.

O. corniculata is a hardy annual with creeping stems. It forms a pretty green carpet with bright yellow flowers during the summer.

O. corniculata rubra is a beautiful variety that has purple foliage contrasting with the gold blossoms. Both of these varieties spread quickly so care must be taken in managing them.

O. rosea is an annual, native of southern Chile. It grows 6-9 inches tall and has bright green leaves and an abundance of pale lilac-pink flowers all summer long. It will grow in dry spots and looks nice under trees.

O. enneaphylla is the prettiest of all the rock garden kinds. The leaves consist of nine blue-green leaflets that are folded in a way that gives them a crinkled appearance. They are carried on pinkish, upright stems that are 3-4 inches long. The trumpet-shaped flowers are large compared to the size of the plant, being 1 to 1 inches across. They are white and waxy looking and have the delicious scent of almonds. This plant blooms in May and June. It isn't easy to grow in most American gardens; it is most likely to succeed in the Pacific Northwest. Not good: it needs a cool position shaded from direct sun during the hot hours of the day.

At the beginning of the growing season, they can be propagated by offsets. They also can be raised from seeds in light, sandy.

Here is additional good info for you from botanical.com:

It is a little plant of a far more delicate, even dainty character, growing abundantly in woods and shady places. From its slender, irregular creeping rootstock covered with red scales, it sends up thin delicate leaves, each composed of three heart-shaped leaflets, a beautiful bright green above, but of a purplish hue on their under surface. The long slender leaf stalks are often reddish towards the base. The leaflets are usually folded somewhat along their middle, and are of a peculiarly sensitive nature. Only in shade are they fully extended: if the direct rays of the sun fall on them they sink at once upon the stem, forming a kind of three-sided pyramid, their under surfaces thus shielding one another and preventing too much evaporation from their pores. At night and in bad weather, the leaflets fold in half along the midrib, and the three are placed nearly side by side to 'sleep,' a security against storm and excessive dews. The flowers, each set on long stalks, are fragile, in form somewhat like the Crane's bills, to which they are closely allied, being bell-shaped, the corolla composed of five delicate white petals, veined with purple, enclosed in a five-scalloped cup of sepals and containing ten stamens, and in the center, five green, threadlike columns, arising from a single five-celled ovary. At the base of the petals, a little honey is stored, but the flower seems to find favor with few insects. As the flower fades, its stalk bends towards the ground and conceals the seed capsule under the leaves, till ripe, when it straightens again. The case of the capsule is elastic and curls back when the fruit is quite ripe, jerking the seeds out several yards, right over the leaves. A second kind of flower is also produced. These are hidden among the leaves and are inconspicuous, their undeveloped petals never opening out. The ripening and seed scattering processes of these self-fertilized hidden flowers are the same as with the familiar white petaled ones. Wood Sorrel droops its blossoms in stormy weather, and also folds its leaves.