WASHINGTON -- For people with a need for a fast-growing barrier plant, the castor bean plant is hard to beat.
It is valuable for a number of uses: to fill garden space; as a handsome live barrier to wall off a neighbor's property, a busy street or an unsightly garage; or to separate a patio from a lawn. The seeds germinate reliably enough, but for those who missed sowing them in May, seedlings grown in plastic pots are available in some nurseries.
It is amazing to watch the seed grow in just one season into an exotic, well-proportioned shrub 8 feet tall or even taller and about as wide or sometimes wider. Glistening in the sun, shiny new leaves seem to form and spread out every day. The plant, known botanically as Ricinus communis, is native to Africa. By late September, the cultivar Zanzibariens has been known to reach a height of 15 feet.
The stems are sturdy and self-branching, and the attractive leaves, which form a dense canopy, can be green, bronze-red or red, as wide as 3 feet in diameter. They look like magnified maple leaves that have grown additional lobes all around.
The castor bean plant has spread like a weed in milder parts of California. But outside the tropics, the plant is an annual. A sunny site is a critical requirement for full size and spectacular beauty. Free of pests and diseases, the castor bean plant has a reputation for repelling moles and gophers.
The seeds are as attractive as beads -- and sometimes are used as beads, but they are poisonous. They yield an oil that has been put to use in parts of Asia as a facial oil and against warts. Today, the oil also is added as an ingredient in paints and varnishes.
It is a one-of-a-kind plant, with only one species -- an oddity in the plant kingdom.
But there is another garden giant well worth cultivating. The angelica is smaller than the castor bean plant and not as dramatic, though it is unquestionably attractive. Up to 6 feet tall and a little less wide, Angelica archangelica develops large clumps of sturdy stems. The leaves are glossy pale green and quickly form a dense fortress. They are topped by dozens of airy, greenish-white flower heads that resemble domes.
A member of the carrot family, this well-loved, old-world plant often is listed as an herb. Every part of it has been put to good use. Its dried roots have been used for centuries as a tonic to fortify the blood and to beautify the skin. James Duke's book on herbal medicine, The Green Pharmacy (Rodale Press, 1997, $29.95), notes that angelica has chemical compounds that strengthen the heart and the stomach and helping to clear the skin. In Europe, the confectionery trade appreciates the taste and the perfume of the flowers.
Angelica will thrive in locations with only half-a-day sun or even more shade. But the soil must be rich, porous and, most important, not allowed to dry out. Many gardeners have lost stout specimens of angelica seedlings because of insufficient moisture, though the plant shouldn't be overwatered either.
The flowering stem soon withers after blooms fade, and the entire plant will die back if too many stems set seeds. Those seeds that do form and fall to the ground are likely to germinate and sprout by the dozen the next year.
Castor bean plant and angelica are annuals that live short but happy lives. They have immense energy but invest none in growing root systems that can survive winter and allow them to return the next season. They live for lavish foliage, and those who love flamboyant plants during summer are lucky beneficiaries.