Lets look at some common plantings around town and examine failure rates, and the reason why they fail. Siberian Elms are resistant, if not immune to D.E.D. (Dutch Elm Disease) and are a fast growing, graceful specimen commonly planted here. Their problem is just that! Besides being a maintenance “junkie” (meaning they must be pruned often, especially if too much pruning takes place at any one time) they just get too lanky for their own good. Wet snow loads simply destroy them! Couple that with poor branch attachment angles, and aggressive rooting tendencies giving them thumbs down in this arborist’s opinion.
Ornamental, or flowering pears share the same downsides, with a susceptibility to the fireblight bacteria and again, it would be far down on my list of favorites!
Any conifer left in a plastic pot for too long in the nursery is a tree to steer clear of unless less a dwarf variety is carefully chosen. I don’t think Modesto Ash trees are even available anymore, but “Raywood” varieties are abound, and is one to be wary of (take your arborist with you to pick out the best one if you must have it)…
Forget Italian Cypress until genetics get back to the way they were in the 1950’s-70’s. They just suck now. Mulberries are great trees, but again, high maintenance.
Poplars are short lived and mountain loving types (aspens, etc.) don’t like temps above high 80’s at all, but in the right spot can work just fine.
Coast redwoods don’t like it here near as much as the Sierra giants, but you can get lucky! Any Birch except the Nigra cultivars is flushing your money down a rathole, so consider yourself warned! Red Maples can really be a coin toss so consult an arborist before writing the check. Japanese maples can be real winners with the exception of verticillium fungal infections that are part of the gamble, but I take that chance often because I love ’em so much!
Cold resistant Eucalyptus is another one I like but there are only a very select few that won’t croak in an average cold winter here. Any tree that begins with Robinia should be avoided like the plague as two weeks of beautiful colors doesn’t make up for the lifetime of “puked” limbs, as well as the thorny hell the eternal rootstock will bring!
Deciduous Magnolias are great trees, but will not tolerate the brutal heat blast that can happen with some cultivars planted in a hot spot.
Dogwoods are just as great; just make sure to put the pink ones in the sun and the white ones in the shade.
Palms don’t count; they are a type of grass.
Zelkovas need to be chosen with extra attention paid to the structure of the individual specimen, lest you get a lemon.
Oaks (my favorites) have a few enemies such as leafy mistletoe or pit scale, but for the most part are pretty much bombproof.
Sweetgums (another limb-barfer) can go either way, but the bad varieties outnumber the good, so be informed before you buy.
True firs (Abies) can work well here, BUT the type of environment you subject them to is critical for success.
Box elders (A maple, really) are among the most regrettable trees you can plant, besides Leyland cypress, of course…
This being the driest winter I have seen here so far, calls for a citywide rain dance!
Plant high, and often…