Almost everyone on the West Coast of California has encountered silver wattle, Acacia dealbata. Some of us know how resilient it is to most methods of eradication. The more fortunate enjoy its magnificently bloom from a distance. It is almost never planted intentionally. It is an aggressively naturalized exotic species. Most grows wild near roadside ditches. Some invades home gardens.
The profuse and bright yellow bloom of silver wattle is spectacular while most deciduous trees remain bare late in winter. Big and billowy trusses of smaller round floral structures obscure most of their slightly grayish foliage. The many individual staminate flowers within this impressive bloom are actually minute. Their hearty floral fragrance is appealing to some, but objectionable to others.
Silver wattle lives fast and dies young. Some trees are so vigorous while young that they are unable to support their own weight. Without appropriate pruning, they simply fall over. Even stable and structurally sound trees deteriorate after about thirty years. Few survive for fifty. They seed prolifically though! Mature trees can get forty feet tall. The finely textured foliage is bipinnately compound.
It is almost never planted in home gardens, but the native red willow, Salix laevigata, has a sneaky way of getting where it wants to be. The minute seeds go wherever the wind blows them. Because it is a riparian tree, red willow prefers well watered spots. If not detected and pulled up in the first year, it can grow rather aggressively, and overwhelm more desirable plants, although the somewhat sparse canopy makes only moderate shade.
It is known by a few different common names, including ‘Andean pampas grass’, ‘purple pampas grass’, and simply ‘pampas grass’. ‘Andean pampas grass’ sounds almost like an oxymoron, since the Andes Mountains are in a separate region to the west of the pampas region of Uruguay and eastern Argentina. ‘Purple pampas grass’ is even sillier, since it is devoid of any purple.
Himalayan blackberry is to cane berries what blue gum is to eucalypti. It is what gives all cane berries a bad reputation, and is why so few of us want to grow them. Himalayan blackberry grows as an extremely vigorous weeds, extending sharply thorny canes over anything within reach. When the canes are removed, the tough roots are extremely difficult to remove and kill.
English ivy, Hedera helix, is probably the nastiest and most aggressively invasive exotic species that I work with. It climbs high into redwood trees and overwhelms understory plants (that live below the trees). It invades many of the landscapes, and worst of all, it climbs building where it ruins paint and causes rot. It grows faster than we can keep up with it.
Just because it ‘can’ be grown as a houseplant does not meant that it ‘should’ be. That is a lesson that Brent and I never learned in college. He and I were roommates in the dorms at Cal Poly in San Luis Obispo, which, as you can imagine, was a problem. Our room on the top floor of Fremont Hall was known as the Jungle Room. It was so stuffed full of weird houseplants, as well as a few plants that had no business inside. We had a blue gum eucalyptus bent up against the ceiling, an espaliered Southern magnolia, a Monterey cypress, and a herd of camellias that we rescued from a compost pile on campus.