IN THE GARDEN NEITHER FRUIT NOR FLOWER - WHAT GIVES?

Byline: JOSHUA SISKIN

E-mails received during the past month:

Q: I planted two avocado trees from seed. I also planted a wisteria vine four years ago. Why don't I have any avocado fruit or wisteria flowers?

- Alice

A: It can take 10 years or longer for an avocado tree grown from a seed to bear fruit. An avocado tree purchased from a nursery may produce fruit the same year it is planted, although, in most cases, three years will probably go by before fruit is seen. The fruit harvested from seedling trees is likely to be bland and sparse. Nursery trees, on the other hand, are propagated for the taste of their fruit and the quantity of their harvest.

Wisteria will not flower as long as most of its growth is in a vertical direction. Only after top growth flattens out for a year or two will flowers be seen. You can hasten flowering by pruning vertical growth.

Q: I kept a Phalaenopsis orchid near my kitchen sink where it would get moisture and it thrived marvelously. But now I am getting worried. The two bottom leaves have turned yellow and one of the middle ones is beginning to color as well. I this natural behavior?

- Marjorie Dudas

A: It is natural for the bottom leaves on any plant to turn yellow before falling off. New growth, not old, should be your focus.

While Phalaenopsis (fal-ay-NOP-suhs) should be kept on the moist side, do not allow it to stand in water. Watering once or twice a week should be sufficient.

Putting a Phalaenopsis by a kitchen window is an excellent idea, as long as the window faces east or west; a partially shaded southern exposure is also acceptable. Phalaenopsis should be grown in a fir bark potting soil and fertilized every other week in warm weather, and once or twice a month in cool weather, with a 30-10-10 fertilizer. Repotting should be done after flowering in the spring.

After Sept. 1 of each year, you may be able to coax a second burst of bloom from your orchid by cutting faded flower spikes halfway back. Cut each spike back to where bud meets stem and you may see new flowers within two months.

Q: Our cherry tree appears to be dying as its leaves are beginning to crumble. I checked the trees around Lake Balboa (in Encino) and they are fine, so I am baffled on this one.

- Anne Donnelly

A: I once planted a cherry tree in Woodland Hills that had to be removed at the end of two years because of excessively burnt - or, to use your word, crumbled - leaves. Although not officially dead, it made no sense to keep the tree in the garden.

You and I planted cherry varieties ill-suited to the San Fernando Valley, whereas the cherry trees at Lake Balboa are perfectly suited to our climate. You probably noticed that the Lake Balboa trees are flowering, as opposed to fruiting, cherries. They are a variety grown exclusively for their blooming capacity. Note: If any reader knows the name of the cherry tree variety planted at Lake Balboa, please contact me so I can tell readers of this column.

TIP OF THE WEEK: If you have daylily clumps that are looking shabby, forget about the tedious job of pulling out dry or yellowing individual leaves one by one. You can simply cut the entire clump of daylilies down to the ground. Within two to three weeks, you will have significant regrowth, with fresh green leaves shooting up where old withered leaves had been. This same procedure works with society garlic, fortnight lilies and liriope.