Arabian lilac (Vitex trifolia ‘Purpurea’)
Photo credit: Cristina Kaisserian / Foter.com / CC BY-NC

Strong and beautiful

Two memorable shrubs, Arabian lilac and dwarf olive, underappreciated in gardens and landscapes until the last year or two, are lately being planted with increasing frequency. A glance at these shrubs will cause even experienced plant watchers to stop in their tracks. Arabian lilac (Vitex trifolia purpurea “Fascination”) and dwarf olive (Olea europaea “Little Ollie”) may soon join that elite group of shrubs that never seem to fail, keeping company with privet (Ligustrum), India hawthorn (Rhaphiolepis), xylosma and mock orange (Pittosporum).
Arabian lilac is an airy, fast-growing woody plant for full- or partial-sun exposures. Planted from a five-gallon container, it grows to a height of 4 feet the first year and 8 feet the second. Unpruned, it may grow even taller and be treated as a small tree.
Most often, it is used as an informal hedge, in which capacity it is pruned hard in early spring. Since it flowers on the current season’s growth (in the manner of hibiscus, crape myrtle and hybrid roses) there is no concern about reduced flower production as a result of late pruning.
Arabian lilacs do manage to put forth small, pale-purple, hummingbird-attracting flower spikes in the summer, but these inflorescences are barely noticeable. The Arabian lilac’s main attraction is its leaves. They are green on top, purple underneath, fragrant and velvety to the touch.
Native to Australia, Arabian lilacs do not need watering more than once a week, will tolerate a freeze and will even grow in somewhat clay-ish soil where drainage is imperfect.
The dwarf olive “Little Ollie” grows slowly to a height of 6 feet. As opposed to the standard olive tree, ‘Little Ollie’ exhibits a dense growth habit. When first placed in the ground, its compact appearance and lush, deep-green foliage will remind you of Pittosporum Tobira “Wheeler’s Dwarf.” Because of its compactness, “Little Ollie” makes a fine container plant. In the garden, it is most often planted as a low to medium hedge and may be kept at any height between 18 inches and 6 feet.

The recent fire came down into our back yard and our 7-foot oleander bushes, which we’ve had for 20 years, were pretty badly burned. Several of the bushes show damage at the bottom and about half of the branches are burned.
Other bushes have branches that are not discolored but are hanging limp. Is there anything we can do now to try and save these bushes?”
Barbara Garrett, Sylmar
There is really nothing you can do to save your plants other than wait. In general, burn-damaged plants should be treated in the manner of frost-damaged plants. Wait until spring before pruning, and leave limp branches alone. If you prune now, you may force out sensitive new growth that would be killed in a frost.
Assess the probability of your plants’ revival by the condition of their stems only. Complete defoliation may occur after a fire without long-lasting effects. On the other hand, if a stem’s outer tissue or bark is burned completely around at the base, it is probably dead. However, if as little as 10 percent of the stem’s circumference bark is intact, it may recover completely. The tissue immediately below the bark is known as the cambium, a layer of active cells that differentiate into xylem (for conducting water and minerals) and phloem (for translocation of leaf-manufactured sugar). This is the tissue that determines the viability of a stem or trunk. For example, the base of a tree trunk may be damaged nearly all the way around, but as long as a small strip of the bark, and the cambium layer below, is healthy from the ground up, the tree may still flourish. String trimmers, also called weed whips or weed eaters, that gardeners use to cut grass around tree trunks may have the adverse effect of killing a tree when the plastic string of the weed eater cuts into the cambium layer of the trunk.

Photo credit: Cristina Kaisserian / Foter.com / CC BY-NC