Susan Shaw from Santa Rosa asks: Are blueberries difficult to grow, and what growing conditions do they need?

Blueberries are acid-loving. Adding copious amounts of well-rotted compost, earthworm castings, redwood/fir needles, and oak leaf mold, along with a little sulfur and an acid fertilizer will bring the soil pH level closer to that ideal acid level blueberries need.

Good drainage is also important. New plants should be mulched regularly and kept well-watered. Blueberries don't like to dry out. An evenly moist soil keeps them happy and healthy throughout their lives. Plant where they will receive shade in the late afternoon. Plant two different blueberry varieties to increase pollination and fruit set.

Deer and birds enjoy blueberries, so protect the plants with netting, especially when they're fruiting.

Don't fertilize blueberries until you see new growth in early spring. The fruit does best with mild fertilizing with each watering once that new growth begins.

Prune blueberries once a year in an open-vase method, just as with roses, right after fruiting and flowering have ceased.

Karen I. From Sabastopol asks: How do you care for Christmas cactus and what to you do to get them to rebloom?

Christmas cactus make much better companions than most of their spiny relatives you may be more familiar with. They seem to have an identity problem, because gardeners never know what to call them. Most bloom from November through January. The early blooming cultivars are "Thanksgiving cacti," while those blooming around the yuletide season are "Christmas cacti." (And don't confuse these cacti with Easter cactus; that's another species entirely.)

Whatever it's called, Christmas cactus makes a fine, easy-to-care-for houseplant, although the foliage is a bit uninteresting most of the year. But gardeners know the joy of anticipation, and once buds begin swelling on this plant, all is forgiven.

Christmas cactus are among the easiest flowering houseplants to rebloom with minimal effort, producing a beautiful annual display of flowers that last three to four weeks. They're available in a variety of colors, mostly centered around shades of pink, but choices can range from white to yellow and lavender to red. Bicolor selections are also available, usually white with pink or red.

Either cool temperatures or short-day conditions — such as those in fall — trigger flowering. If the average temperature is below 60 degrees F, flowers form regardless of day length. But if the temperature is in a more hospitable range between 60-80 degrees F, plants initiate blooms once nights are longer than 12 hours. Little effort is needed to take advantage of the conditions that trigger flowering.

Simply leave the plant outside during summer and fall and allow the changing season to do what comes naturally, then bring plants inside around mid-October. It takes about six weeks from the time buds are first visible in October until plants bloom. (Allowing your Christmas cactus to dry out once buds begin to form will result in the buds dropping from the plant.)

Once the plant is moved inside, provide bright light such as in front of an east-facing window, uniform moisture supply (water when the top half of the soil in the pot feels dry to the touch) and keep away from heater vents to ensure the buds continue to develop.

Once your holiday cactus has bloomed, treat it as you would any houseplant. When the danger of frost has passed, move the plant outside to an area with bright light, but not direct sunlight. Fertilize occasionally and water as needed. They'll tolerate dryness, but they shouldn't go too long without water during summer.

(Send your gardening questions to The Garden Doctors at pdgardendoctor @gmail.com. The Garden Doctors can answer questions only through their column, which appears twice a month in the newspaper and online at pressdemocrat.com.)