IN THE GARDEN PERSISTENCE CAN RID YARD OF IVY AND BAMBOO.

Byline: JOSHUA SISKIN

Q: Help! The home we moved into this year was planted with invasive bamboo and an excessive amount of ivy. Are there any tips or tricks for permanently removing them?

- Blistered and Tired in Northridge

A: It may not be possible to permanently remove ivy and bamboo, but persistent efforts to contain them, over an extended period of time, will discourage their growth to the point where they are no longer a nuisance in the garden.

While both bamboo and ivy are invasive pests, they are much different botanically. Bamboo, classified as a giant grass, has the same persistent underground rhizomes as certain subtropical lawn grasses (such as Bermuda and Kikuyu), allowing it to recover from periods of drought. Yet the rhizomes of bamboo are not deep and may be dug out with the help of a mattock and trenching shovel. Still, some roots may remain from which fresh shoots, in spring and early summer, will grow.

Ivy does not have underground storage organs such as rhizomes - just highly resilient roots. If you dig out a patch of ivy without getting every piece of root, the ivy will regenerate itself soon enough.

Systemic chemicals used for killing weeds will not kill ivy or bamboo. The least backbreaking way to eliminate bamboo and ivy is to cut all growth to ground level and religiously cut back new growth as soon as it appears. By preventing new shoots and leaves from developing, you stop photosynthesis - the process by which plants make their own food - which eventually starves the underground root system.

Still, where ivy or bamboo once grew, you may see occasional shoots or leaves pushing up through the ground that will have to be pulled out to prevent reinvasion of your garden. To prevent the horizontal spread of bamboo, you can contain it with a 2- to 3-foot-deep barrier. Root barriers are sold in the garden departments of home improvement centers and at nurseries.

By the way, there is an excellent Web site on bamboo at www.americanbamboo.org. Everything you ever wanted to know about bamboo, including details on how to get rid of it, can be found at this site.

Once you bring your ivy or bamboo under control, you will find the soil they grew in to be a fantastic location for new planting. The pervasive roots of ivy and bamboo do an excellent job of aerating the soil to a 2-foot depth, making it soft and highly plantable. The roots of new plants will grow easily in such soil and establish themselves practically overnight.

Q: I have four camellias, but only two of them are blooming. The other two have had buds since before Thanksgiving but will not open. This is the second year that this has happened. Last year I pulled off all the buds at the end of the season. This year I pulled off buds if there were more than one on the stem. What can I do to get them to open?

- Terri Glaser, Simi Valley 

A: I am going to assume that the camellias that do not open are not the same variety as those that do open. You describe a rather common occurrence among camellias. It is known as bull-nose syndrome because the buds get rather large - if not quite the size of a bull's nose - but then wither or drop off without opening.

You might have a camellia variety that requires a certain amount of cold for its buds to open. Alternatively, certain camellias may be more sensitive than others to water deprivation or excess, so you may want to make sure that your soil is evenly moist throughout the year.

Excess fertilization might also prevent camellias from flowering, since they are not heavy feeders. You are wise to prune some of the buds from your camellia, because too many buds on a single stem can prevent all the buds from opening. Finally, fungi have been implicated in irregular flower-bud development in camellias.

TIP OF THE WEEK: Many camellia varieties do not bloom until February or March, so do not despair if your camellia has not yet flowered. The best local site for viewing camellias is Descanso Gardens in La Canada Flintridge. The collection of camellias at Descanso has an international reputation and is one of the must-see horticultural attractions in our area. For information about visiting times, call [phone]; www.descansogardens.org.