I have just returned from England where I was surprised to notice how many large trees are being felled by strangulation by ivy. Whole forests were full of dead trees leaning precipitously but held in place by thick ivy. Some ivies develop trunks up to 6" in diameter and as the vines twist and grow around the trunk of the host tree they slowly stop that tree's ability to thrive. Occasionally I saw that ivy had been cut from large ancient oak trees, but that varied depending on the landowner. Ivy has had a long time to grow in England, but it has not been in California for very long, and see how prevalent it has already become.
This lovely hybrid from two California native salvias blooms in spring. It's a perfect choice for hillsides because it spreads laterally, never growing more than two feet high. Salvia Bee's bliss will not like irrigation, particularly overhead, after the first couple of years in the ground.
Just look at this horror, botanical name Delairea odorata. It's just like kudzu. This ivy climbs to the tops of trees and strangles them to death. It's interesting how many invasive plants have so much form in common with each other, growing solid green blankets over everything in their path.
Let's not use them! Pesticides kill just as many beneficial insects as pests. If you have severe problems use Safer soap just before dark (so that bees and butterflies are not on the plants). Even dishwashing liquids like Ivory liquid or Palmolive, diluted and sprayed using a spray bottle, will kill citrus leaf miners and aphids. The surfactants in the soap suffocate them. Again, do this in the evening every two weeks.
If you have roses, and there are aphids on the buds, put on a rubber glove and gently squish them off.
I don't know why it is but the sun seems more dazzling these days and my plants scorch in summertime unless they are at least lightly shaded. Quercus agrifolia, California live oak, is the most practical shade tree in California. Although this species has a reputation for slow growth, after the first ten years they take off like rockets and become enormous eventually. If you plant one, choose a tree with all of its lower twigs and branches intact. This will encourage the trunk to grow strong. The lower branches can be trimmed off later on. The grand Valley oak grows even larger, and is deciduous (a winter advantage) but it is susceptible to oak root rot fungus and it is probably unwise to grow this beauty in a city garden.
Platanas racemosa, California sycamore is a beautiful deciduous tree with large hand shaped leaves. It naturally grows near streams and is not drought tolerant. Grow it if you have a spring or creek. If this tree is stressed by drought it will suffer from blight and drop leaves at any time. The Arizona cultivar is not as susceptible to the blight and you can recognize it because it does not have the characteristic mottled trunk of the California native.
Arlington Garden, 295 Arlington, Pasadena, CA is a lovely place to take a picnic in spring and has a good range of native plants, augmented by mediterranean plants and a few succulents and cactus.
Beverly's garden at the Sam Maloof Foundation, 5131 Carnelian Street, Alta Loma, CA 91701 is definitely worth a visit because the use of unusual native plants is so successful, particularly in late summer and fall. Many plants have been chosen for their super seedheads and dormant color. The foundation website contains a complete list of plants in the garden.
The Theodore Payne Foundation, 10459 Tuxford, Sun Valley, CA 91701 has a nice native demonstration garden, and a nursery too.
March 26, 2010. I heard that familiar scritchy call and there it was, as usual, in the Grevillea. Orioles love this plant, and Melianthus too, which is not blooming yet.
Grevillea Long John is a big rangy plant, but it can be hedged nicely with quarterly pruning. I like mine to be natural and it is a large shrub or small tree with narrow leaves a bit like pine needles. It blooms almost year round and is popular with hummingbirds too who always nest in it.
If you plan a pond, plant waterlilies and other floating plants to cover the water surface and prevent evaporation. Be sure and put in some mosquito fish to keep your pond free of mosquitos. A pond should have some connection to ground level so that frogs can come and go. Believe me, frogs can be stupid and they won't walk the plank.
If you have very sandy soil, a drip system may not be the best solution because the water will not spread around the root ball but drains away quickly instead. In this case you will have to continue with overhead watering or hand watering the individual plants if you have the time and inclination. Drip systems work well with normal or clay soils. Many native and drought tolerant plants do not like to have warm wet roots in summertime. Water early in the morning, but try not to water at all during heatwaves unless unusually prolonged. If a heatwave is forecast, water the day before so that your plants can take up the water and protect themselves.
Note that all plants, drought tolerant or native species or not, need water when they are fresh in the ground, and for the first couple of years until a good root system is established. A new garden should be planted in late fall or early winter to take advantage of winter rains to get the roots down. The plants will be healthier and will need less water in the spring and summer.
If you plan to install a birdbath, be sure that you can refill it easily as water evaporates quickly in hot weather.
These pictures show two plantings under oak trees, the one on the left receives morning sun all year round, whereas the one on the right only gets morning sun in winter when the neighboring sycamore loses its leaves.
The characterful plants on the left never need maintenance and, after a couple of years, will virtually never need water. These are fire safe plants.
Bromeliads and many succulents (shown on the right) do well planted under California live oaks, and because they are drought tolerant and very shallow rooted they do not affect the soil negatively.
The quickest way to improve the health of your soil is to stop blowing your garden as if you were vacuuming your living room carpet. Blowers are stripping the soil of nutrients and blowing the topsoil away. Leaves should remain under plants, or be composted and returned to the beds later. A thick layer of compost or mulch around plants will prevent evaporation and, as it rots down, will replenish the organic matter in the soil. In the Los Angeles area, free mulch is available from several sites, see www.lacitysan.org/srpcd/mulch_giveaway.html. Sometimes this free mulch will have small pieces of plastic or glass in it so be careful if you have children or pets. Mulching will tidy up and unify the appearance of the garden at the same time as it provides insulating shelter for roots, worms, and necessary bugs. Mulch should not be piled up around the root crowns of trees because it can encourage destructive fungi to thrive.
Cloramines are now the purifier of choice for most of our water agencies because it has no aroma. Unlike clorine, cloramines do not break down and evaporate quickly. Instead the clorine evaporates out of the molecule leaving ammonia residue in the soil. Ammonia is harmful to all life which is why we cannot top up our fish ponds with tapwater without using a modifier to get rid of the ammonia. Likewise, ammonia may harm soil bacteria and that is another good reason to irrigate your garden as little as possible.
One of the most comprehensive waterwise plant lists available online is provided on the Arizona Municipal Water Users Association (AMWUA) website, www.amwua.org. Click on Landscape Plants to find well organized lists of plants, with photographs, in all categories.
Oh, what to do with all those sticks and vines? Well, you can roll them up into a large ball, cutting and bending where necessary, adding to it each time you clip. When it is a big old thing, just roll it into a shady corner of the garden and let it become a nice covered area for birds to scratch in.
Look what we found in the garden today: a praying mantis larvae case. it looks as if the larvae have fled the coop and we will have some nice big mantises stalking around the garden in summertime.
Our mantis population grows every year and we love those quirky looking creatures. They take forever to pounce on their prey! They move so slowly that birds catch them alas, but everyone needs to eat.