This year I'm recycling my Fatshedera. It is a real aristocrat of green plants and besides is something of a botanical marvel: The tree ivy.

Fatshedera is known botanically as a bigeneric hybrid. Most of our ornamental plants are hybrids, results of crosses between species within the same genus. Fatshedera originated from cross-pollination of one genus with another genus of the same family, Araliaceae. Such crosses don't happen often. It has been compared to the breeding of a mare and an ass, of which the offspring is an animal different from either of its parents.

Fatshedera is the result of a cross that occurred in the Lize Freres Nursery in France in 1910; its parents were the Irish ivy and Moser's Japanese fatsia. And so we have the tree ivy.

The plant combines the shrubby character of the Japanese fatsia with the five-lobed leaves of the Irish ivy. The result is a semi-erect vine-shrub that can be tied to a support or allowed to grow as a bush up to three feet tall. It is hardy in Zone 7 of the Arnold Arboretum scale, which includes the Washington metropolitan area. Tree ivy is a popular garden plant in the south; in the north it is much used as a tall-growing indoor ornamental.

Fatshedera has been variously described as semi-climbing or somewhat shrubby. My plant never did put on its "somewhat shrubby" character. It seemed to want to be a vine, and two years ago it got too tall for its appointed place in the house. At that time I decided to test its winter hardliness.

Since then it has spent the summers on the patio and two winters in a window well on the south side of the house. This spring it is putting forth a number of green buds down low on the trunk, suggesting an inclination to branch as a shrub.

Another characteristic this plant has inherited from its parents is ease of propagation. I propose to take advantage of this trait to get some additional plants while bringing the old plant down to a more manageable size.

Three nice-sized sprouts at the top will be removed with a sharp knife and potted individually in a 50-50 mixture of sand and peat. Watered and bagged in plastic, the pots will be set in the shade of an azalea until growth is apparent at the tips, indicating that roots have formed.

Then the plastic bags will be opened and the plants gradually exposed to the air so that they can adjust to the vagaries of the outside environment. Soon after, they will be ready to be transferred to pots of rich soil and held in a light shade until time to bring them indoors in the fall.

Meantime, the old stalk will be cut down to about six inches, leaving probably two of the new side shoots. Removed from the pot, with some of the roots pruned back to compensate for removal of the large amount of top growth, the old plant will be repotted in fresh soil to get a new start in life.

There will remain about two feet of the old stalk. If sprouts of impressive size are present, stem cuttings will be made so as to use every piece of the original plant. The cuttings will be treated in a manner similar to that used for the three top branches.

Although Fatshedera has proved itself hardy as I have handled it, the new plants will be kept as house-plants at least for the first year.

Indoors, Fatshedera is a good plant for a north window exposure, in a hallway, stairwell or other low-light situation. Temperatures of 50 to 70 degrees are suitable. Like ivy, it needs moist soil. During the winter it doesn't grow noticeably, so it requires less frequent watering and no fertilizer. For spring and summer feeding, a weekly application of water-soluble houseplant fertilizer at half the strength recommended on the label is adequate. The plant is placed outdoors in the spring in its pot in a semi-shady place. Although I was willing to risk leaving my plant outdoors in winter and it survived the rigors of the last two winters. I should caution that such treatment is not generally recommended.

Fatshedera is said to be susceptible to the same pests that attack its ivy relative - spider mites, scale, mealy bugs and aphids. I have not had encounters with these pests probably because my plant, along with numerous others, received frequent brisk showers from the garden hose in summer.

Fatshedera is impressive in its own right for its lush columnar greenness. Knowing of its hybrid character adds an element of special interest to ownership of this plant.