Garden Docs: How much to prune back a woody butterfly bush?

Tom G. asks: I have a buddleia that is large and very woody. A few of the stems are large, making it more difficult to prune. Last year I pruned it back to a height of around 4 feet. Gardening friends have suggested I prune it back even more. What pruning guidelines do you suggest?

Buddleia, also referred to as the butterfly bush, can be selectively cut back to a height of 12 to 18 inches above the ground. Any large, woody stems should be cut back to the ground, encouraging new fresh growth in their place. Since buddleia are summer/fall bloomers and begin their new vigorous growth first before setting buds, plan on selective pruning in early spring - say the month of February.

As a note of interest, the method of cutting to the ground certain shrubs annually is called “stooling” and is done to promote bigger blooms. Let us know if your buddleia produces gigantic blooms next summer.

Ed writes: After reading your previous column about colorful shrubs that produce berries and have winter interest along with their other attributes, I would like to recommend Mahonia repens, an evergreen low-spreading form of Oregon grape.

Thank you for the suggestion. Mahonia is also known as Oregon grape because of its clusters of blue or blackberry-like fruit. It is available in many sizes; a tall favorite is “Golden Abundance,” which grows to 6 feet high and 5 feet wide. Mahonia x media “Charity” is even taller, reaching a height of 15 feet and 12 feet in width. Mahonia pinnata, California grape holly is more reasonable in height, 4 to 5 feet by 45 feet wide. It is a native to California and southern Oregon.

Mahonia “Compacta” grows 2 to 3 feet in both height and wide. Ed, your favorite M. repens, will reach a height of 1 foot and a width of 3 feet. Repens spreads by underground stems and is one of the best for winter color. Deer usually avoid Mahonia but it does attract birds and butterflies.

All the Mahonia have spiny holly-like leaves, masses of yellow flowers followed by berries and some foliage coloration in cooler weather. It performs best in a part sun/shade exposure and requires occasional water. It is considered a candidate for a firescape garden and helps erosion control on slopes.

Julie R. asks: Are Washington hawthorn berries poisonous to dogs?

No, they are not poisonous to dogs, cats or horses, according to the American Society for the Prevention of Cruelty to Animals. The bright red-orange berries are food for birds and other wildlife in fall and winter.

Victoria asks: How does one identify the difference between carpenter ants and termites?

Capture, if possible, a few samples of each insect. Examine their body shape and you will see that carpenter ants have a thin narrow waist and two distinct body segments. Termites have broad waists.

Next, observe their wings. Both insects have four wings. But termite wings are the same size and pointed. Carpenter ants’ front wings are somewhat larger than the hind pair and are paddle shaped.

The life stages of both insects are different. Termites have a “gradual metamorphosis” - egg, nymph to adult.

Ants have a “complete metamorphosis”- egg, larvae, pupa to adult.

Termite galleries are evident by piles of hard seed-like fecal pellets or have wood shavings and insect parts.

Carpenter ants have hollowed out galleries that are smooth and clean, with piles of fine sawdust and insect parts called “frass.”

Control ants by placing bait near their trails. There is another effective granular bait called Maxforce. Purity Chemical on Maxwell Court should carry that particular product. Follow their instructions.

There are several ant bait stations available and Amdro bait is one where the ants crawl into the plastic station and take the bait back to their nest. It can be used inside and outside and easily tucked away so animals and small children cannot get to the bait.

The best advice for control of termites is to hire a registered pesticide applicator or talk to people at Purity Chemical for advice.

Dana Lozano and Gwen Kilchherr are garden consultants. Send 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.