Thursday, June 10, 2010
Narrow Screening Plants for Southern California, Part I
Below: Oh please, oh please, let that Arbutus grow a little taller:
For narrow screens many people think of Bamboo, which has its own set of problems. I'll ignore the bamboo question until I can get down the road to take pictures of a property where a narrow bamboo screen has become a property completely overrun with bamboo.
I live visual privacy. I can't quite get audio privacy, but I assumed visual would be easy. It's proven more difficult than I first thought, because I want plant screens but I desperately don't want Ligustrum japonicum.
Ligustrum japonicum is commonly known as Privet. There are other members of the Ligustrum genus also called Privet, and the Wikipedia entry says another couple of genera are also known by that name. It is a wonderfully tough shrub that eventually, limbed up, can become an surprisingly elegant small tree. I like it as a small tree, but not as a screen. It's as common as dirt around here, and with good reason, because it can survive everything but a bulldozer. I got it into my head that I wants hedge plants that are not as common as dirt, and I've been avoiding Ligustrum japonicum ever since, choosing to search for something less common. This has proven unsatisfactory.
I should mention what I mean by "narrow": Six feet (2 M) wide or less. Six feet may not seem "narrow", but remember plants need space for their roots, and while there are choices less than six feet, there are not a lot of choices. I will discuss some, but most of the plants are six feet or so, some trimmed down to that with modest to moderate effort, some naturally that approximate width. Height on most of these is more than 10 but less than 20 feet. Some are taller, some shorter.
Take Dodonea viscosa 'Purpurea'. I planted a hedge of six. One, perfectly lined up to screen out my neighbor's bathroom window, the rest would screen out the neighbor's roof. They grew fast, if not dense. They are fairly green in summer and fall, then grow purple in colder weather. Just exactly as the Dodonea grew large enough to screen out the window, as I looked out the bathroom window to soft purply foliage instead of neighbor, Santa Ana winds came along and blew the critical Dodonea, over snapping most of it off. Arrrgggghhh!!
D. viscosa is a prodigious reseeder, though seedlings are easy to pull out, even when the volunteer is several feet tall. To add insult to injury, it isn't quite as dense as I'd like, though it has become denser with age--six years now. I've limbed the survivors up and am starting to top them before they become so tall I won't be able to top them. That should provide more foliage density, making them a little more satisfying.
Dodonea screening out a roof, or it did, anyway, until the wind knocked one down and killed it:
I replaced the fallen Dodonea with a volunteer seedling, decided that one would probably get blown over as well, and am trying again with 'Euonymous japonica 'Chollipo' . My excuse: it was on sale! 20% off! Fresh from the grower! Exactly the proportions desired, 12' tall, 6' wide, fast growing, according to Monrovia. Dense! Tall enough! And fast! Fast can't be fast enough at this point. I have some of the diminutive Euonymous japonica microphylla. They're incredibly tough, surviving zero water and terrible scale infestations, coming back again and again.
Prunus caroliniana is another screening plant I'd wish a little denser. Some modest trimming would possibly help, mine are completely untouched. There's a disease called shot-hole that attacks the leaves, but mine have not been much affected. All in all a decent tall screen. Mine are 15-18' after 10 years, but they were past 12' at 3 years. Good, but not as good as plain old Ligustrum. and P. caroliniana also appears inferior to my neighbor's Prunus ilicifolia, a Southern California native shrub.
My neighbor dug up and replanted some local volunteer seedlings from the existing native population of P. ilicifolium and they look great. Some heading back and light shaping were involved. I'm waiting for ripe seeds from the local wild specimens, to replace a couple of the P. carolinianas in my own garden. P. ilicifolia appears to be faster growing than P. caroliniana, and the foliage is a slightly deeper, richer green.
Syzygium paniculatum, commonly known as "Eugenia" in Southern California. Once it was the King of the Narrow Screen--you can shear it to 18" and still get a dense solid wall of foliage. Then the Eugenia psyllid arrived. An excellent explanation here at the San Marcos Growers site about the Eugenia psyllid that ruins the best narrow screen plant Southern California has ever had. Mine have been okay as far as the psyillid goes; it's the rain and the Santa Ana winds that have been a torment. I got eight healthy plants, and put them in as a screen for yet another neighbor's intrusive window.
The Syzygiums grew fast, looked increasingly beautiful--and then the Santa Anas arrived and snapped three of them off at the base, including of course the one right in line with the neighbor's window. The snapped off trio grew back quickly--they are at nine or ten feet now in their new multi-trunked incarnation--and all eight of them looked beautiful again, until late spring rains made them all hunch over like little old people.
Just can't win. Now they seem to be straightening up again with the arrival of summer. Patience. Five years is not enough. Another five I hope will create a solid Syzygium wall and privacy for both us and the north side neighbors.
Podocarpus is often used as a tall screen in Southern California. These are planted on four foot centers and trimmed several times a year:
If the plants are too close together, they may not fill in well because they are all fighting for sunlight, but given time and regular trimming, they get fairly dense.
Podocarpus species used for hedges include P. gracilior, P. macrophylla, P. macrophylla 'Maki', and P. henkelii. P. gracilior in nature can easily get 50 feet tall, so keep in mind that if you use it as a hedge, you'll need to control it.
I have more examples of narrow screening plants. I'll do that in the next post.
Update 5/22/2013 I'll add a link to a page which discusses California native plants as hedges--some are narrow, some are not. If you are interested in a native plant hedge, this is a great resource.