Silver Wattle

Silver wattle is a magnificent weed.

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.

Horridculture – Clinging Vines

P91113Ivy often climbs into trees, buildings and all sorts of other situations where it becomes problematic. It might have been planted intentionally. It might have grown from seed left by birds. When it gets into trouble, we can easily blame it on the ivy. Even that which was planted was intended to be mere ground cover. It only climbs out of control because that is what ivy does.


This Boston ivy that . . . ‘someone’ planted almost a year ago was actually expected to climb. That is what Boston ivy does. Even if it would be willing to grow as a ground cover, it would not work well as such because it is deciduous. As a climber, it covers freeway sound walls and any associated graffiti with vibrant green foliage that turns fiery orange and red this time of year.

The problem with it is that there are not many practical applications for it. Yes, it does well on freeway sound walls. It also does well on concrete parking structures, where it can not reach painted or wooden surfaces. There are a few unpainted reinforced concrete building out there that it would work nicely on, as long as it gets trimmed around windows, doorways and roofs.

It has no business on painted wooden surfaces, or even stucco. It clings with these weird ‘suction discs’ that never let go! (They do not really use suction, but an adhesive instead.) You can see a few to the right in this picture below. When vines get pruned back every few years, the suction discs remain attached. Although not a problem for concrete, they promote rot in wood.P91113+

What concerns me with the Boston ivy in these pictures is that it grew to the top of the pillars that they were planted on in less than a year. Even if they get pruned down this winter, they will grow farther next year, and will reach the wooden bridge above. It will be a lot of work to keep them pruned back from the bridge.

As you can see I the picture below, Boston ivy is quite pretty on the concrete. Fall color is delayed this year. P91113++

Red Willow

P91108It 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.

With a bit of grooming, red willow can be a handsomely asymmetrical tree, with upright branch structure. However, even the healthiest trees rarely get more than thirty feet tall, or much more than forty years old. The leaves are a bit shorter and wider than those of the more familiar weeping willow, and do not color as well in autumn. There are actually a few other native willows that are also commonly know as red willow. Some are quite similar, while others are very different.P91108+

Cortaderia jubata

P90908It 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.

I know it simply as ‘papas grass’. That is just how I learned it. The problem with this common name is that it is the same common name of Cortaderia selloana and its cultivars, which is a distinct species that is, on rare occasion, planted intentionally in landscapes. Cortaderia jubata is one of the most aggressively invasive of exotic species on the West Coast, so is not planted.P90908+

Cortaderia selloana is safe to plant because it is ‘supposedly’ sterile, so can not naturalize. Technically though, it is not really sterile, but merely exclusively female, without male flower parts for pollination. It reproduces by apomixis, which is a fancy way of saying that it produces viable seed without pollination. No one has bothered to explain why that makes it any less invasive.

Cortaderia jubata reproduces by apomixis too, but makes much more of problem with it. It is very prolific with its unpollinated seed! To make matters worse, it will hybridize freely with Cortaderia selloana if it gets the chance. How does that even work?! Pollen is needed for that sort of hanky panky! Nonetheless, the hybrids are almost as aggressive as Cortadera jubata is!P90908++

I just don’t trust any of them. Cortaderia selloana cultivars can work well in large landscapes in urban areas, where they can not escape into the wild. For rural or suburban landscapes that are near wildlands, there are plenty of other less invasive options.P90908+++

Bad Picture Of Good Berries

B90803KHimalayan 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.

If ignored, the canes ‘leap’, which means that they develop roots where they arch back downward to touch the ground. From there, they grow into new plants that extend new canes in all directions, to start the process all over again. (‘Leaping’ is like ‘layering’, which involves the development of roots where stems ‘lay’ on the ground.) Their seed gets where their canes do not.

The thorns are ‘prickles’, which really is a technical term for sharply pointed distensions of bark or epidermis. They are more like stout prickles of rose canes than the more finely textured prickles of garden varieties of cane berries. They are rigid, extremely sharp, and curved inward to snag victims on their way out; so are seriously wicked and potentially dangerous to handle.

Harvesting berries from second year canes is not easy. Most are out of reach within bramble thickets. Because they ripen through a long season, they must be harvested repeatedly, as those that were unripe during a previous harvest finish. This is why there are black, red and green berries in the same picture. The berries are small and variable, with good years and bad years.

This happens to be a good year. The thorny truss of a few small berries in the picture may not look like much; but there are plenty of them. The berries are quite richly flavored too. Those who have the patience to collect them will get some good jam or jelly out of the deal.

Horridculture – Ivy League

P90306English 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.

English ivy is actually a nice ground cover plant for refined landscapes. I grew it at my home in town. Contrary to popular belief, it does not root into and parasitize the trees that it climbs. Actually, it rarely overwhelms and shades out large trees. It prefers to keep them alive for support, from which it disperses its seed. However, it does promote decay in the trunks that it climbs, particularly where it retains moisture at ground level. Native trees are not accustomed to that.

We try to remove as much English ivy at work as possible, which includes removing it from trees and buildings. So far, with a few exceptions of small bits of ivy that broke off high in the trees that it climbed, I have been able to remove all ivy from the trees and walls that I have worked on.

Others were not so fortunate. When quick and efficient removal of ivy from the bases of as many mature trees as possible is the priority, ivy is more often severed down low, and left to die on the trunks of the infested trees. It looks shabby to say the least, and takes many years to deteriorate and fall away. In the picture above, dead ivy that was severed within the past few years is already being replaced by new ivy, which will also need to be severed.

The same technique happens with ivy on buildings. It gets cut at the foundations, but left on the walls to shrivel and turn brown. The dead ivy in the picture below was reaching upstairs eaves when it was severed, and remains there a few years later.

What annoys me so much about this technique is that it does not take much extra effort or time to tug quite most of the lower ivy from trees and walls. For most situations, all ivy can be dislodged, although tiny aerial roots remain. It is much easier to dislodge while fresh than after it is dried and crispy.P90306+

Very Bad Houseplants

P71230Just 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.

After college, our own homes were no better. Because my dining room was rather small, Brent gave me tall weeping figs that had unobtrusively bare trunks down low, and plenty of fluffy foliage pressed up against the ceiling; a technique we did not quite perfect with our Jungle Room blue gum. I had a giant yucca in the guest suite, a redwood in my bedroom, king palms in the parlor, and a lemon gum eucalyptus over my desk in the office. The bathroom was the worst, with pothos and Algerian ivy hanging over the shower curtain, and billbergias up over the shower. A pair of small birds nested in the billbergias, and before I realized that they were there and evicted them, they started a family!

At least Brent kept most of his plants outside where they belong. The staghorn ferns grab onto the walls when they get the chance. Wisteria vines grab onto anything else. The flame vine climbed up the chimney (appropriately), and before Brent knew it, had sneakily spread to the opposite side of the parapet roof! Then there was the giant timber bamboo. Yes, that is what I said; giant timber bamboo. I know what you are thinking right now, so there is no need to say it.

There is a narrow space between north side of Brent’s home and the concrete driveway next door. It is almost three feet wide. Brent though that if he planted the bamboo there, it would not get to the other side of the driveway. He was actually correct.

Did I ever mention how vain Brent is? Well, that is another topic for another time. I will say for now that he has more clothes than his teenaged daughter Grace. A lot more. They do not all fit in his big closet. He hangs some of his longer coats that he does not need very often in Grace’s much smaller closet. One day, he was reaching around the clutter that is common in a teenaged girl’s room, and groping for one of his coats in Grace’s closet, when he grabbed a hold of something that should not have been there. He was not certain what it was at first, but when he found his coat and pulled it out, a few dried bamboo leaves came with it and fell onto the floor!

The bamboo did not even try to go under the neighbor’s driveway. Instead, it went under the foundation of the house. Where it came up, it had nowhere to go, so somehow weaseled in next to a water pipe, and followed it up behind the bathroom washbasin. Once inside, it somehow weaseled past a valve access panel behind Grace’s closet, and straight up to the ceiling. What is even funnier is that Grace knew it was there, but figured that it was just another one of Brent’s crazy landscaping ideas!

Just in case you are wondering, giant timber bamboo is a very bad houseplant!

The bamboo is gone now. It got so tall that the wind would blow it against the terracotta tiles on top of the parapet wall. Also, the foliar litter was too messy on the parapet roof and the neighbor’s driveway. It did not contribute much to the landscape anyway, and shaded only a driveway that is seldom used.