Default Header Ad

European White Birch-Clumps

Question from Darla:
I just read you response to someone regarding their birch trees.  I had planted yesterday, for the second time, three European White Birch-Clumps at the side of an apartment building in a coastal area of Southern California.  Previously, I lost five trees on the East side of a two story building (two city approved trees on the parkway and three birch in the small lawn area).  I lost all trees within a few years.  I had just removed the last birch stump and it appears there was root rought.  After reading your response to another birch grower, you mentioned moist soil and an adequate water supply.  I noticed that the sidewalk adjacent to this area holds water for several hours after the sprinkler system has ended.  I guess my question is, how much water is too much.  I really want my birch trees to be successfull this time.

Answer from Pat:
Though Sunset Western Garden Book correctly states that European white birch (Betula pendula) will grow in Zone 24, it often succumbs to borer attack. People love this tree because it reminds them of the east coast and is very pretty in front yards. Thousands are sold in Southern California. A few of them survive for a few years, and thousands more die, usually after a few years. So how much water is too much? Here is the answer: European white birch needs regular irrigation, so in well-drained soil, watering with as much as 2 inches or even 3 inches of irrigation per week is never too much, but if the tree is planted in an area with poor drainage, then even 1 inch of rainfall or irrigation water is too much. If you have planted your new trees in a spot with poor drainage your chances for success are slight, and you are between a rock and a hard spot. If you water with less than an inch of irrigation per week your trees will die or do badly and eventually succumb to beetle attack. If you water with more than one inch, and there is no drainage, then your trees will die from root rot.

Another factor affects the amount of water plants need and that is the type of soil you have. (See pages18 to 23 in my organic book that discuss soil problems and pages 36 and 37 of my book for information on irrigation.) Note the “Rule of Thumb” in italix on the bottom of page 37: “One inch of water will penetrate sandy soil about 12 inches, loam about 7 inches, and clay soil only 5 inches, perhaps less.” If you planted in clay soil without proper attention to drainage, you could be soaking the top layer of the soil while roots are dry at the bottom, or alternatively you might be allowing the planting hole to fill up with water and rot the roots since it has no escape route. A tensiometer would let you know the depth that water has penetrated, but if water is not draining you need to fix the problem.

Your best solution would have been first test the drainage and fix it if necessary and then plant the trees. Since you planted your trees last week, it’s not too late to dig a sample planting hole three feet away from the trees and of the same depth as you dug for the trees last last week and do a drainage test as described in the box on page 40 of my book. But if water is left standing in that spot after the ground is irrigated, you already know it has bad drainage. My opinion is you had better dig up the trees, and either mound the soil, or build a raised bed and plant the trees in a raised bed. (See page 41 in my book for details.) Also, if you have clay soil, throw a few coffee cans full of gypsum into the bottom of the planting hole and dig it into the ground on the bottom of the hole. If poor drainage is due to compaction caused by alkalinity of clay soil, adding gypsum to the soil will help improve the drainage. (See pages 21 and 22 for complete explanation.)

Finally, please think again of the description I wrote to another reader about a perfectly planted and well-grown grove of European birch trees (Betula pendula) in Brentwood. Note they were growing on mounded soil but the soil was well-drained decomposed granite. I once saw another, though smaller, picture-perfect garden planted in a similar way on a hill in Zone 23, within view of the ocean. The trees had no protection from the west sun or wind and the soil was clay. The owner of the house was an excellent gardener, but in this case, after about six years the trees died. He wisely did not try again with more white birch. This time he replaced them with a subtropical flowering tree, better adapted to our climate. He chose a red African tulip tree (Spathodea campanulata). It’s now a magnificent specimen that flowers massively for several months in summer and fall every year.

If your birch trees die, you might replace them in that narrow spot with a grove of paperbark trees (Melaleuca quinquinervia), not one of my favorite trees but usually a caste iron plant for difficult situations.

Comments

  1. We have a very large white birch tree in our back yard. It is 25 years old and the trunk is about 1-1/2 feet in diameter.
    We noticed a number of holes in the trunk about 10-15 feet above the ground. They are at least 3/8 in. in diameter and some are in rows about 2-3 in. apart.
    We live in Anaheim Hills, CA, about 6 miles East of the Anaheim civic center.
    Any ideas?

  2. if the tree is still alive get a treatment for bronze birch borer (look it up for more info)because that’s what is attacking your tree

    • Bronze Birch Borer (Agrilus anxius) will almost always attack white birch trees eventually and it is a difficult pest to combat. Since I am an organic gardener, I try to help all people with their garden problems, but I do not believe in growing things that will not survive in our climate unless sprayed with poisons. It is my opinion that most white birch trees belong in this category. My attitude is get rid of the trouble makers and try to love something else. Nonetheless, it is true that healthy birch trees that have no root rot can make a lot of sap and fight off bronze birch borer. On the other hand it is impossible for a tree to make adequate sap to fight off borers if it has root rot. Birch trees will always get root rot if they do not have good drainage. Spraying with poisons will not fix this problem. A possible organic control for borers is WormGold earthworm castings spread under the tree over the root zone and covered with a one-inch layer of compost. This treatment might help the tree to absorb adequate chitinase to destroy the chitin which makes up the exoskeleton of insects, including bronze beach borer. Non-organic and poisonous sprays, such as bendiocarb or permethrinare, are available to control bronze bird borers but I do not recommend their use. These poisonous insecticides must be applied by an professional arborist or pesticide company to kill the larvae in early spring before they bore into the tree. However, severely infected trees should first be removed or the borers from the infected trees will overwhelm the healthy ones. Now to discuss the straight lines of round holes that sometimes occur in bark. Straight lines of round holes are most likely made by woodpeckers. Bronze Birch Borer (Agrilus anxius) makes D-shaped holes and they are not lined up in a row. Also when a tree has been attacked by this insect the ridges on the tree will be swollen and packed with sawdust.

  3. I had a beautiful white European clump birch tree when I lived in Riverside Ca. I had three or four trunks about 10 to 15 feet long and some smaller trunks also trying to grow. They were wonderful along with some rocks around the clumps in the front yard. almost no work just year round beauty. I purchased them and planted it myself and other than a little good soil and regular watering, just beauty. I had them about 15 years and want to replace what I had. My pride and joy!!!

    I now live just south of Salt Lake City. I would like to have a 5 or 8 feet foot long clump of the same type tree. Can you help me or advise me where I should shop to
    find what I’m looking for? I totally love everything about the tree. Regards, Coach Roach

    • I suggest you look for tree farms in your area. If there are none, visit a good nursery near where you live and enquire if they have this tree or can order it. I live in Southern California and most of my advice is for the Mediterranean climate. Your new location is an interior climate. I am sorry I cannot help you further.

Leave a Reply