IN THE GARDNE TREE ROOTS CAN BE UPLIFTING - NOT IN A GOOD WAY.

Byline: JOSHUA SISKIN

Q: I live in an upper-level townhouse, and my neighbor below me has a ficus tree planted in her patio garden that has literally grown to the top of the building (probably at least 25-30 feet high). I read in your column how the roots can get out of control, and I already notice that the walkway that I share with her in front of the tree is already cracked and raised. What kind of damage are these roots doing underneath the surface? Should I be concerned about ruptured underground pipes, etc?

- Cindi Milrad,

Granada Hills

A: I am assuming you are talking about Ficus nitida, or Indian laurel fig, one of the most popular Valley trees. Its foliage is a comely chartreuse color, its trunk is whitish-gray, and it is evergreen. It makes a wonderful hedge that can reach a height of 30 feet.

Mature Ficus nitida specimens will be damaged, and young trees even killed, by the sort of hard frost we experience every 10 years or so. Ficus nitida is also attacked by thrips, a dark,thread-like insect that curls its leaves. But the biggest problem with Ficus nitida is its root system.

Yes, this tree will crack sidewalks and street curbs and any other hard surface in its path. It is native to the tropics, which means its roots will grow along the surface when water is plentiful. If you must grow this tree, give it a minimum of water - no more than a once-a-week soaking when it has established itself in the ground, about one year after planting.

Ficus roots will grow into pipes, but so will the roots of sycamore, podocarpus, jacaranda and just about any large tree. I remember when the roots of my neighbor's majestic jacaranda tree grew into my sewer line. I had to pay to have a new section of line installed. My neighbor had a more severe problem and seriously considered removing the tree before he decided, at great expense, to reroute all the major piping in front of his house in order to save the 50-foot-tall jacaranda. The trunk of my neighbor's jacaranda is less that 3 feet from his living room window.

Even at this late date, when we should know better, new homes and townhomes are built with trees planted within a few feet of the outer walls.

Q: I have allowed my lettuce to go to seed (small yellow flowers) and am now enjoying the 3 1/2-inch-high shoots (very milky), but I do not see anything resembling a seed. This is my first - albeit exciting - time with the ``Front-Yard Garden.'' How do I harvest the lettuce (and broccoli) seeds?

- Bette Biers,

Granada Hills

A: Wherever you see a lettuce flower, you should eventually get seeds. The seeds are about 1/8-inch in size and crinkled. You could buy a package of lettuce seeds at any nursery to see what they look like. I know when I first started looking for seeds, it seemed that I would never find them. This is where patience comes in. In an increasingly ``got to have it now'' culture, the garden may be the only place where patience is essential to success.

TIP OF THE WEEK: How do you know when your soil has been successfully amended? - when you see seedlings of your flowers, shrubs and trees sprouting in it. Create such a soil by working in soil amendments such as compost, leaf mold and straw.