ONE OF THE BEST FASTIGIATE OR COLUMNAR OAKS is the English oak, Quercus robur. There are many wonderful types of oak trees and not all of them grow 100 feet tall and 80 feet wide. Most English oak varieties generally only grow 45 feet tall and 15 feet wide. Some of course can be larger or smaller, with size dependent on variety.
MELDING THE CHARACTERISTICS OF ITS WHITE AND ENGLISH OAK heritage to produce a fast-growing and hardy, columnar tree, Quercus robur x Quercus alba ‘Crimson Spire,’ is very typical in its size as a hybrid. One parent is the English oak and another parent is the white oak. Its columnar habit is inherited from its English oak side, while its unique characteristic of attractive rusty or reddish fall color is inherited from its white oak side.
KNOWN FOR BEING VERY HARDY the English oaks are also very drought-tolerant, not as sensitive to soil pH as most oaks, and they adapt well to small areas and tough urban conditions. If that is not enough to convince you, consider how well its dense foliage can make an impressive screen and can block sound during the growing season. Its beautiful dormant shape continues the show into winter.
LEAVES ARE GENERALLY BLUISH TO DARK GREEN in color and are roughly one-half the size of its white oak parent at 2 to 5 inches long and 1 to 2.5 inches wide. Its foliage resembles that of white oak with leaves having rounded lobes, apex, and base. Most English oaks have fall color that is brownish at best, so look for Crimson Spire if fall color is important.
PLANTED SINGLY, AS A HEDGE, OR IN SMALL GROUPS or groves, English oaks are equally beautiful in all situations. They are appropriate for sites limited on space but are also very beautiful when planted where space is not a problem.
ASK THE GARDENER
by Angie McManus
Q I have a hillside of junipers with a blue rug type on the outside and taller ones in the center. They are 8 years old and the center plants are brown and dying. Any suggestions?
A There could be a few different reasons why the junipers in the center are not happy. It has been such a hot and dry summer that even established plantings require supplemental water when Mother Nature does not provide enough rainfall. Junipers require full sun, a minimum of six hours of direct light to thrive. If they are not getting enough light, they will become stressed and are more prone to insect and disease issues.
There are many species of juniper and some are more disease-resistant than others, but spider mites are a common problem. We usually notice the symptoms before we notice the tiny mites. Look for webbing along the branches. Yellow-brown foliage on evergreens on the inner part of the plant is a normal annual shedding.
Are the evergreens brown just in the center or are they brown throughout? Unfortunately, once evergreens turn brown it is usually too late to help them. If the majority of the plants are brown, they should be removed.
You can take a sample to your County Cooperative Extension office and the agent will be able to give you a more definitive diagnosis and treatment options to help save your junipers.