Q - The top two feet of my 15-foot-tall Chinese juniper turned brown almost overnight. What kind of terrible disease could have caused it? It was such a beautiful tree.

A - It probably was due to a gardener somewhere in the neighborhood spraying with a weed-killing chemical such as 2-4-D. With even a little bit of of wind, the chemical can be blown and cause serious damage a block away. To prevent it, preach and practice: Don't spray when the wind is blowing!

Q - We have a beautiful Japanese red maple; can we take cuttings from it and root them?

A - Cuttings from almost all Japanese maples are difficult to root. It can be done with some varieties under intermittent mist with bottom heat. Most kinds are propagated commercially by grafting, using seedlings of certain varieties as rootstock. Layering is a fairly successful method. A low-growing branch with new growth on it can be used. Early spring is the best time to do it.

Q - We have a wisteria that never blooms, two dogwoods that bloom very sparsely, a lilac that never blooms although its neighbor does, our holly tree has no red berries. Does this happen to other people?

A - Wisteria stated as a sucker from a blooming plant may not bloom for 15 or 20 years; the same is true of the old-fashioned lilac; dogwoods do not bloom well in rather heavy shade; male holly trees bloom but don't have berries, and female holly trees will bloom but not have berries unless there is a male tree nearby for pollination.

If you have a question for Tom Stevenson, write to him at the Weekend section, The Washington Post, 1150 15th St. NW, Washington, D.C. 20071 .