Last year, my serrano chile pepper had a highly variable amount of heat. One week they were very hot, the next week very mild. Does overwatering or cool weather make for milder peppers?

Last summer, I tried growing a single heirloom (Brandywine) tomato plant. I got lots of blooms, and the plant grew very tall (about six feet) but got only one tomato. Thinking it was a pollination issue, I tried shaking the plant, and experimented on a couple of flowers by trying to pollinate by moving a Q-tip around in the flower.

Neither attempt worked. Any ideas why I got such a poor yield?

– Walter Floyd, Orangevale

According to UC Master Gardener Bill Pierce, chile peppers are native to the tropical regions of North and South America and need heat to perform well.

With most fruits – from trees or vegetables – too much water destroys the true flavor. A deep soaking – wetting the soil to a depth of 18 inches and using a mulch of 3 to 4 inches thick – should be enough for peppers every 10 to 14 days.

Heirloom tomatoes are fickle. One season, they will swamp you with fruit and the next be as stingy as your plant was.

Tomatoes, because of the structure of the flowers, are self-pollinating plants. When planting heirlooms, you may wish to also plant one or two hybrid varieties to get a reliable crop of tomatoes.

Hand-pollination is a tedious chore, but sometimes necessary. The pollen is yellow and is produced on the structure in the center of the male flower.

You can use a small artist's paintbrush to transfer pollen, or you can break off a male flower, remove its petals to expose the pollen-bearing structure, and roll the pollen onto the stigma in the center of the female flower.

When hand-pollinating, it is important to use only freshly opened flowers. Flowers open early in the morning and are receptive for only one day.

I have a fruitless plum tree that constantly drops its leaves. Every morning, I have to sweep about 40 to 50 leaves. Is this normal? Is there anything I can do to eliminate this?

– M. Meyers, Grass Valley

Sometimes when plum trees are sunburned, they drop a lot of leaves, according to UC Master Gardener Bill Pierce. Did you prune the tree heavily last winter or spring and expose branches to the sun?

When trees are pruned heavily, the best practice is to paint the limbs that are now exposed to the sun with diluted white interior latex paint to prevent sunburn.

Do the fallen leaves have holes in them? Shot-hole fungus affects plum trees. The leaves look as if they were blasted by a shotgun and fall off. To remedy this, spray the tree during the dormant season with fixed copper or sulfur spray or an artificial fungicide such as Daconil.

Is the tree planted in a lawn and is lawn water the only irrigation it receives? If so, it may not be getting enough water to support all the foliage and is aborting the excess.

Lawn trees should be given a deep soaking; get the moisture down to 18 to 20 inches once a month during the dry season. Wind a soaker hose under the tree, beginning at the drip line, and let it run for several hours.

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