Q My father was an avid gardener who grew many unusual plants. One which stands out in my memory was a perennial with purple flowers that gave off fumes which would flare up if a match was held near them. If I knew the name, I would search through my perennial catalogs and order some.
The plant is Dictamnus, commonly known as the Gas plant or Dittany. Besides the purple-flowered one (purpureus), there is a white (albus) and a rosy-purple one (rubra).
All have the added attraction of being very fragrant, but the seeds are toxic , so keep them away from small children.
Q Some of our raspberry bushes produce fruit that appears to be only half formed (sometimes less). The year before last there appeared to be only a few plants, but last summer almost all our plants had some fruit such as this.
If the berries are very small and seedy, or soft and crumbly, it would likely be due to mosaic or anthracnose. The only solution to this would be to remove the bushes. Then buy inspected bushes from a nursery and plant them in a different area of the garden.
If firm flesh forms on only one side of the berry, this is an indication that the flower buds were attacked by tarnished plant bugs (one-quarter inch oval, tarnished-looking beetles) that suck juice from one side of the bud, making the fruit malformed.
You have two choices: You can spray unopened flower buds thoroughly with Sevin, a pesticide that breaks down quickly, or you can use the all-purpose formula: 1 tablespoon each of liquid household dishwashing detergent and hot pepper sauce mixed with 1 gallon of tepid water.
Sevin is toxic to bees, but you would be using it on unopened buds, so the bees would not be present.
Q I want to confirm your statement that Jerusalem artichokes will take care of themselves once established. About three years ago I bought some tubers in the produce department of a grocery store. After eating some, I planted the rest. They come up every year with no special care. In late fall I dig the tubers and put some in a refrigerator, and they keep for months, retaining crispness and flavor. I always have enough to share with neighbors.
We want to thank the many readers who commented on Jerusalem artichokes. The vote was that they are tasty, long lasting, and nutritious, besides being hardy (in cold areas as well as hot) and carefree.
Further, they have beautiful golden blooms that can be used for cut flowers.
Q I would like to graft several varieties of apples onto one tree. When is the proper time to do this and where can I get detailed information about it?
Grafting with a scion (piece of stem with leaf buds) is done either in the spring while the tree is still dormant or just as the buds begin to swell. Budding (using a bud with a small piece of bark attached) is done in July, August, or September.
There are several methods of grafting, many of which are illustrated in our ''Green Thumb Book of Fruit and Vegetable Gardening.'' However, you can probably get a bulletin on grafting from your state college or county cooperative extension service.
(Editor's note: A few weeks ago a reader wrote to this column and asked about a pamphlet that lists some of the shrubs that can be planted in order to attract birds. So far we have received more than 3,000 requests - and counting.)
If you have a question about your garden, send it to the Garden Page, The Christian Science Monitor, One Norway Street, Boston, Mass. 02115. Doc and Katy Abraham are nationally known horticulturists, authors of several books on gardening, and greenhouse operators for more than 25 years.