IN THE GARDEN

Arkansas Democrat-Gazette azalea bark scale illustration
Arkansas Democrat-Gazette azalea bark scale illustration

Q [Last] summer some of my azaleas showed white specks on black branches. Now it has spread to other bushes, and they don't look too good. One of the small ones lost a lot of leaves, and the mulch underneath it turned black. Summer 2015 I sprayed with a fungus and insect killer, but it didn't help. I try not to use too many pesticides because I don't want to harm the birds that eat insects. Should I remove the bushes?

photo

Special to the Democrat-Gazette

Spotted in a Little Rock restaurant, this stem of dianthus is a newer, green variety.

A Without seeing them, I suspect you have an azalea bark scale, which is similar to the problem we are having on our crape myrtles. The insects attach themselves to the stems and suck the sap out of the plant, giving off a sticky honeydew. Wherever the honeydew is, the stems and leaves turn black from a sooty mold byproduct. I would suggest using a systemic insecticide immediately after flowering this spring. Imidicloprid (Merit or Bayer Advanced Tree and Shrub Insecticide) can be mixed with water and poured around the drip line of the shrubs. The plants will take up the insecticide and move it throughout their parts. This should have no effect on the bees or birds as the flowering period will be over. For a positive ID, take a branch sample to your county extension office. If it is scale, we have found that one application of the insecticide seems to help for two years or so.

Q When is the best time to prune blackberry canes for the coming season? Any special tips I should know? Also, we have ashes from burning some tree limbs. Would some of these ashes be good to work into our garden soil?

A If you still have the remains of last season's blackberry fruiting canes in the garden, remove them. I try to remove the canes as soon after harvest as possible, but sometimes we get busy. Once a blackberry cane bears fruit, it dies. The new canes that are produced during the year are the ones that will bear the following season. I would not use many, if any, wood ashes in the garden. They can be high in salts and will raise the pH -- a little goes a long way. Instead, add them to a compost pile or mix with leaves and let them decompose.

Q I believe my dogwood tree has a fungal disease that will eventually kill it. I heard the disease can spread through roots to other plants. We have some azaleas nearby. Should we remove the tree? Treat it? I'm not one to pay for a service to spray our trees.

A I am not sure what disease you are referring to. Is it a root-rot problem or a foliar leaf-spotting disease? Root rots can be a result of poorly drained soils, which can affect other plants, but I don't know of any dogwood disease that would affect other plants. Before removal of the tree, make sure you know what disease you are dealing with and how much damage has been done to the dogwood. Sometimes they are too far gone to save, but if the problem is a leaf-spotting disease, we can turn things around with good sanitation, fungicide sprays and nutrition. Take a sample of the problem to your local county extension office for proper identification.

Q This plant was on the table of a restaurant in Little Rock. The waitress did not know what it was. Can you help?

A It is a new variety of dianthus, or what your grandmother called "sweet William" -- it is either "Green Ball" or "Green Trick" dianthus. It is related to the common carnation. It should be a fairly long-lasting cut flower and would be perfect for St. Patrick's Day.

Q When is the appropriate time of year to plant a camellia? I only have one of these winter-blooming beauties but would like more -- or any other winter-blooming plant suggestions.

A The camellias have been and are gorgeous this year. There are two basic types most commonly sold in Arkansas nurseries. The Camellia sasanqua is hardy statewide and has small flowers in late fall and early winter. The Camellia japonica is hardy through half to three-quarters of the state. Japonicas are the ones that are beginning to bloom now. They have larger and showier flowers but can be susceptible to a late frost. Many nurseries carry the plants year-round but are likely to have the best selection now. The dormant season is a great time to plant larger trees and shrubs, but you could plant through the spring and again in the fall. I avoid planting in the heat of summer since watering is much more critical then. Camellias need a well-drained, acidic soil with morning sun and afternoon shade.

Janet B. Carson is a horticulture specialist for the University of Arkansas Cooperative Extension Service. Write to her at 2301 S. University Ave., Little Rock, Ark. 72204 or email her at

jcarson@arkansasonline.com

HomeStyle on 02/18/2017

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