Street Trees and Black Bamboo

jacaranda trees

jacaranda trees

That tree growing in your parkway (the little strip between sidewalk and street) can have a significant influence on your daily life.
Aside from determining how much light reaches the plants in your front yard, and therefore affecting your decisions about what to plant, your street tree can affect your mood, especially when you come home at the end of the day. It’s the first thing you see, after all, as you approach your home.
Does your tree give you brightening and uplifting flowers – or contemplative shade? Or perhaps your tree gives neither but is instead a stately column, such as a Canary Island pine, that stands like a silent sentry, protecting you.
Do its roots run just below the soil surface and depressingly push up your sidewalk’s concrete slabs? Perhaps your tree is a risk whose brittle branches, in the manner of eucalyptus, might fall on you if you park underneath.
If such is your case, you can appreciate what it’s like living in the shadow of a volcanic mountain, never knowing when it might erupt. Or perhaps, like a sycamore, your parkway tree possesses a unique and reassuring fragrance, which is most noticeable after a rain.
If you are lucky, you live on a street where a single tree species grows all along the parkways. Arboreal repetition of this sort can take your breath away. When you see large, mature trees arching up and over any street, the feeling is sublime. But this feeling may be truly special in Los Angeles, as compared to other metropolitan areas.
Ours is a city built on dreams of overnight fame and overnight riches, and untold numbers of people, transient and rootless, have flocked here to attain them. Arches of mature trees, by contrast, impart a sense of permanence, and so you are taken aback, not quite understanding at first, but quickly warming to the feeling engendered by their presence.
If you should be in the vicinity of Stansbury Avenue, for example, just south of Ventura Boulevard in Sherman Oaks, it might be worth making a detour to experience the jacarandas that are growing there. Without quite knowing why, you will want to linger on Stansbury Avenue, walking under the trees or just sitting back in your car, not desiring to be anywhere else, to drive to wherever you were headed, or to answer your cellphone when it rings.
The city of Claremont has many streets where a single species of tree has been planted. These tree-lined streets impart dignity, serenity and a sense of history to their neighborhoods. In 1889, immigrants to Claremont from Eastern states sought to replicate the arboreal beauty of their college towns.
To this end, trees native to the East Coast were planted. Most notable among them were American elms (Ulmus americana), many of which can still be found on Indian Hill Boulevard. American elms are no longer planted in many parts of the United States, including California, because of Dutch elm disease, but you can still see some of their noblest specimens in Claremont.
Q: A few years ago I purchased black bamboo from a nearby nursery and it is now outgrowing its boundaries. I like the screen it’s created between my property and my neighbor’s objectionable backyard view, but it’s outgrowing the heavy plastic barrier I installed and I’m wondering if a permanent concrete barrier would work better. Can you tell me if the bamboo would find the alkalinity of concrete desirable and thus grow into it, destroying the concrete? I would appreciate any help you can give me. The only other solution offered me is to cut it all down and pour gasoline on it or try to dig it up, which could be an ongoing project. The nursery that sold it to me led me to believe it wouldn’t runner as much as other running bamboos. I would be very grateful for any and all suggestions you might have.
-Marilyn Mellon
Woodland Hills
A: While black bamboo (Phyllostachys nigra) is not as aggressive as golden bamboo (Phyllostachys aurea), any running bamboo can eventually create problems. A concrete barrier, while expensive, will be effective. Yet you could save money by installing a bamboo rhizome (root) barrier, readily available through Internet vendors. Your barrier was probably too thin to hold back the bamboo. It must be at least 60 mil (.06 inch) thick and, to be safe, two 60 mil barriers should be placed back-to-back and sunk to a depth of 28 inches to make sure rhizomes do not eventually poke through.
Bamboo rhizomes will be more easily controlled by careful preparation of the planting area. If you ever built a raised bed for growing vegetables, you will know how to proceed.
You begin by mixing compost, straw, sawdust, manure or other organic materials into your soil to a 12-inch depth. This will ensure quick establishment of your bamboo.
Bringing in fast-draining topsoil and more amendments, you will then want to create a tapered bed that rises 6 to 12 inches above ground level. As long as the soil that surrounds the rhizomes/roots is soft and inviting, rhizomes will grow into it instead of diving underground.
Your root barrier should be installed so that there is at least 1 foot between it and the bamboo. Several inches of the barrier should protrude above ground level, serving as a header or border for your bamboo bed.
Twice a year, in August and October, take a spade and carefully circle the perimeter of your bamboo planting, chopping through any rhizomes that have extruded beyond the borders of your stand of bamboo. Make sure you dispose of these cut rhizome pieces. If you leave them in the ground, they will sprout new bamboo shoots.
Extensive information on bamboo culture and maintenance may be found at http://shweeashbamboo.com.
Incidentally, the Japanese Garden in the Sepulveda basin, part of Los Angeles’ Tillman Water Reclamation Plant, is the best local spot for observing bamboo species, both running and clumping types.
Tip of the week
We tend to think of heaths and heathers as plants from the Scottish Highlands that crave a rainy climate and acidic soil. However, there is one heather that Valley gardeners can grow, and it is a perpetual delight to those who do. It is Cape Flats Erica (Erica verticillata), so named because of its South African Cape habitat. This Erica develops into an airy 5-foot shrub with short, prickly green foliage and clusters of tubular pink flowers that may bloom at almost any time. The flowers fade to an attractive burnt orange and remain on the plant for more than a month. This feature comes into play when you are considering long-lasting vase arrangements. I have cut woody, foot-long Erica stems and kept them in an inch of water for weeks, their foliage and drying flowers looking as good as the day they were detached from the mother plant.

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