Just thought I would note that I purchased two oleanders last summer ('07) and that they over wintered without protection in Abbotsford on Sumas Mountain. This winter, I intend to burlap them though. I got a little busy in December and didn't do that last year and was scared I would lose them. Because of our excessive rains this year ('08), I did get yellow leaves with black spot, but took those off the plant. Let me know if you are growing oleander in Zone 8 or lower and what your experience has been. I love this plant. It is very showy. I have it pruned like a lollipop at the start of my driveway and it has a twisty trunk, too.
Grown by some people in Seattle but should always be considered experimental here - note that these are ubiquitous in the landscaping of warmer climates yet seldom seen here. If they were well adapted here, they would be all over here as well. If you are up some ways, in a foothill climate you will surely have to protect these periodically in order to keep them there. Some cultivars are more hardy than others. You said you had seen some "black spot" on yours. 2007 edition of Sunset Western Garden Book mentions that Oleander was once the basic landscaping shrub for regions with hot, dry summers and mild winters, but it is now facing a severe threat from leaf scorch, a bacterial disease spread by the glassy-winged sharpshooter (an insect pest). Leaves of infected plants turn brown and drop, and the plant quickly declines and dies. No cure is known, although the disease's progress may be slowed by pruning out affected parts of the plant (sterilize pruning tools after each cut). The disease is already serious in Southern California and in parts of Arizona and Texas. Efforts are being made to curb its spread by controlling the insect carrier. Previously, chief problems were scale, yellow oleander aphid, and bacterial gall disease (causing deformed flowers and warty growths)
I currently have three specimen of Nerium oleander in the garden. One pink, basically planted 2 years ago once I tired of moving it. Another, 'Hardy Red' that is new this year and finally a small cutting that has done well and most likely 'Hardy Red' as well, a gift from a neighborhood gardener. I'd imagine -8 celcius (18 F) of short duration would be the limit for these. I'm not sure if these would re-sprout from old wood or be root hardy after such a freeze. Cheers, LPN (Barrie)
Mine look no better here on the Island. I did take plenty of cuttings last autumn though. Cheers, LPN.
