Question: I have an 8-foot-tall dwarf Alberta spruce in my yard. Near the top, it has a longer shoot that has longer needles. It looks like I have two different trees on the same plant. What's going on?

Answer: Dwarf Alberta spruce (Picea glauca "Conica") is a popular dwarf conifer for landscape use. It is dense and slow-growing to 10 feet tall. Occasionally, it will develop a reversion, a fast-growing shoot that wants to be a full-size spruce. These shoots can be pruned out when seen, so that the dwarf character of the plant is retained.

Q: I have two pinyon trees planted in my yard that are now over 20 years old. Cones form and there are nuts that form in the cones, but there are no seeds inside. How do I get the tree to make edible nuts?

A: Pines, including pinyon, are wind-pollinated and cross-pollinated from other pine trees of the same species. This means that pollen from a pinyon tree will not pollinate itself - it only results in a dried-up papery "skin" inside the shell. Even though you have two trees, there is not sufficient "stand density" or sufficient pollen to develop mature seeds or nuts. The same would happen with another wind-pollinated plant, corn. If you only planted two cornstalks, there would be insufficient pollen to develop any full ears of corn; instead, you might see only a few scattered kernels on the ears.

Even if you had 25 pinyon trees in your yard, nuts would not develop every year. There is also some dependence on weather conditions, including when and how much rainfall is received. Pinyon nut shells with a light-tan color have only the papery skin inside; chocolate-colored shells are much more likely to have seeds.

Q: One of my houseplants has white fluffy masses on the stems. What is it? Do I need to spray something?

A: The cottony fluffs sound like mealybugs. They are soft-bodied wingless insects that suck sap out of the plant. Their feeding may cause leaves to yellow as the plant weakens. Isolate a plant infested with mealybugs immediately. If the infestation is light and only on one or two plants, the pests can be handpicked or removed with rubbing alcohol. Take a cotton swab, dip it in the alcohol and touch it to the mealybugs.

Robert Cox is the Colorado State University Cooperative Extension horticulture agent in Arapahoe County. For information on many horticulture topics visit plant talk.org.