Friday, April 20th, 2012...7:58 am

Deodar Cedar Issues – Part II

Evening fog by autan

In a post earlier this week TheGardenLady gave an answer to a question from a Katherine about a problem she is having with her giant Deodar cedar tree.  TheGardenLady has more to say on this topic.

There are three major things plants need to grow and thrive. The first is adequate light for the plant species. Most flowering plants like sun. Very few plants will put out flowers if there is not sunlight or light. The second requirement is water or moisture. Every plant has a certain moisture requirement. And last, plants need nutrients. They take nutrients from the soil or sometimes from water, especially if nutrients are added to the water.

When you have a large tree, it wants a lot of the light, water and nutrients for itself. And when you have a large evergreen tree, it usually takes up the light and under the tree, it is often too dark for other plants to survive. The second need the tree has is for water. A massive tree will have massive roots that are searching for water that falls to the ground and its leaves, or needles, also absorb some of the water as it falls. So any plant that could grow under the tree has to be pretty drought tolerant- unfortunately most shade loving plants love water, too. And finally nutrients, a huge tree is using its roots to get nutrients for the tree, so a plant that is trying to grow under a large tree is going to have difficulty trying to get nutrients for its needs. This is besides the fact that evergreens drop those needles that make the soil acid. And not all plants can grow in all Hardiness Temperature Zones. So you see why you are having such a difficult problem.

You can do a little amending. People don’t generally limb up evergreens because you want that shape with those graceful bottom branches. So light will be a problem for most plants. But there are a few that grow in low light that you can experiment growing under the tree. You may have to water any plants more than you normally would because the large evergreen will be vying for the water. You will especially have to water when you first plant something and at least until it becomes established. And as far as nutrients go, you should get the soil tested to see the pH so that you don’t plant the wrong plant in the wrong space. But some minor amending of the soil can be done if the soil pH is not completely out of whack. If you can find spaces to plant anything, because the roots of the tree may not allow planting, you can try to stick in some plant. You don’t want to cover any roots of the evergreen that are above the soil because covering roots can kill a tree.

Here are a few plants that you MIGHT have success planting. I do not know your Hardiness temperature zone but since you are in the Los Angeles area your temperature zone is either 9 or 10. A watering system, such as a drip system, might help these plants get the water they need. (see here)

Acuba Japonica. This shrub grows in Temperature zones 7 -10. It likes partial to full shade. And it likes moderate to dry conditions. The pH conditions are 5.1 to 5.5 (strongly acidic) 5.6 to 6.0 (acidic) 6.1 to 6.5 (mildly acidic)

This shrub has variegated or spotted leaves that might look cheery in the shade of the cedar tree and it has red berries. For a list of some of the varieties of Acuba check here.  I worry that your area might be too dry for this plant’s needs so that you will be watering a lot. But some sources say it can tolerate moderate to dry conditions.

There seem to be more possible plants if you live in Temperature Hardines Zone 9. Besides being able to grow Acuba, you might have luck with a shrub called Nandina domestica or Heavenly bamboo. There is one variety with red berries and another ‘Alba’ has white berries. Both have showy white flowers. It will grow in shade and acid soil. Whether, you have too much shade and acid soil has to be seen (see here).

For a list of plants that grow in shade, the list gives water requirements,too, you can check here.  Of course you will have to check to see if the plant is hardy in your Hardiness Temperature zone and also if it can take the acidic quality of the soil.

The Deodar Cedar is native to the Atlas Mountains of Morocco and Algeria in the Middle East. This tells TheGardenLady that it will be even more difficult to find something to grow under it.

The other suggestion is to forget having plants and create a small sculpture garden. Find art that you enjoy, perhaps from up and coming young or starving artists. Maybe they would be willing to show the piece on your property for a short period and do it for free, so that you will have a changing exhibit.

Or consider a stone garden like they have in Japan (see here). Be careful and do not pile the stones too heavy or deep on the roots of the tree which has to breathe. And you will have to blow the needles off if you want it to look pristine. Then you can ” plant” interesting rocks in your garden or rock basins or Japanese lanterns (see here) for a real zen look. And if you want, you can strategically place some containers with flowers that will grow in the shade, like the impatiens or begonias.

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