Summer sales and drought defense
Tue, 09/05/2006
The end of summer is a good time for nursery visits - whether you are preparing a new garden or renovating an existing one. Nurseries begin to reduce inventory in August as they prepare for the new year.
You'll find lots of sales to move plants that have been around since spring. In addition to the benefit of reduced cost, potted plants are now large and filling their containers - unlike new spring transplants. So, get out their and support the industry.
Q: I have a hot south facing wall where I'd like to put a climber. I've tried evergreen clematis and they just fried in the sun. What would you suggest?
A: Campsis radicans (Trumpet vine) or Bignonia capreolata (Cross vine) both love the heat and need lots of sun. Deciduous Trumpet vine clings to surfaces with holdfasts similar to English Ivy. The large dark green leaves are intricately divided and fern-like. While the species looks like an orange-red waterfall in bloom, newer cultivars display yellow or deeper red flowers. The trumpet flowers attract hummingbirds and loads of bees
Cross vine's generally red on the outside and yellow inside tubular blooms also attract hummers and bees. A semi-evergreen (depending on the severity of winter) vine, it climbs by way of tendrils similar to sweet peas. Several new cultivars have expanded the color range including the exotic 'Tangerine Beauty' with its rosy shades of peach.
Native to the southeastern US, both are vigorous woody vines that can grow 20 to 50 feet. Strong support is needed whether grown on a wall or trellis. Completely hardy in Puget Sound gardens, sun is the one absolute necessity for heavy bloom. Drought tolerant and happy in poorer soils as long as it drains well, Trumpet vine and Cross vine are luxuriant accessories for a hot sunny location.
Q: What would you recommend to cascade over and disguise a retaining wall? I have one of those engineered concrete block walls and would like to high it. It gets mostly sun and things seem to dry out quickly.
A: Prostrate rosemary and Ceanothus 'Point Reyes' are both excellent subjects to drape over a sunny retaining wall. Both do well in dry locations and poor soils. In fact, excess moisture is a death blow. Native American Virginia creeper (Pathenocissus quinquefolia) will grow along the wall offering deep green leaves in summer turning bronzy red in fall, then a tracery of branches during winter months.
If the site is moist, a good choice might be Boston ivy (P. tricuspidata). Not actually an ivy, this deciduous broadleaf vine can be trained for 50 to 60 feet along the wall. It has reddish-bronze new growth that turns glossy, dark green in summer and changes to orange red in fall. This vine bears clusters of blue black berries favored by birds. Boston ivy and Virginia creeper are both very vigorous and will cover your retaining wall in short order. Be careful to keep them out of trees, as they can overwhelm.
Q: I've noticed a lot of leaves dropping from trees in my neighborhood. Is there a disease or something that's killing them?
A: The likely culprit for leaf drop this summer is premature dormancy triggered by drought. July through August has been the second driest summer ever recorded in Puget Sound. We've seen less than a tenth of an inch of rainfall for the period. No wonder trees are reacting. Drought dormancy is a defense mechanism to prevent severe injury.
Don't begin a regime of watering where trees are entering dormancy. It would only cause soft new growth that would be killed in a couple months by early frost. Water dormant plants sparingly to keep them alive yet not trigger new growth. Apply no fertilizer or make any soil changes as both will have adverse impacts.
Given the nature of our increasingly dry summers, it might be time to think about replacing trees that require copious water with drought resistant specimens. Think 'respond' to the environment rather than 'react' to it.
Do you have a question for "Lazy Gardener" Stephen Lamphear? Email him at lazygardener@comcast.net.