Xtremehorticulture

When Should I Prune My Vitex Tree?

Q. When should Vitex tree be trimmed and how much should be cut? Vitex in its winter form A. Vitex blooms in early summer through late June or July. If this plant is pruned with a hedge shears you will likely affect how it blooms this summer. Larger vitex in late June Vitex with flowers in June Any pruning done now should selectively remove entire branches back to a crotch. This is a pruning technique called “drop-crotching”. This technique reduces the size of a plant while still retaining its natural form. Drop-crotching avoids plant injuries due to “topping”. Vitex in bloom in May Limbs that add height or size are removed at the juncture with a branch of smaller size. This type of limb removal maintains terminal buds at a lower height, retains flowers and maintains the architecture of the plant. The opposite of drop-crotching is topping, or shearing the plant at a desired height or size. We do not want to do that to most trees. After reducing the size of Vitex we would remove any crossed branches or broken branches and shape the tree to maintain its symmetry.

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Olive, Vitex or Crape Myrtle. Which is best?

Q. You helped me out a couple of years ago when I had questions about growing tree roses.  Now I would like your opinion on some tree varieties. This fall I would like to replace a couple of sumacs in my back yard. I really like three trees: olive, chaste and crape myrtle but I can’t find anything online that compares these three trees.  Do you have a favorite?  Can you give me some pro’s and con’s compared to each other? A. These three trees are dramatically different from one another in many ways, are used for different purposes in the landscape and have different watering requirements. All three will work here, Crape Myrtle being more difficult to manage than Olive or Vitex. Crape myrtle growing in desert soil Comparing all three trees, crape Myrtle provides the most year around beauty in the landscape. All of them are relatively slow in getting some size so you might shop for some larger trees if you want some instant impact after their planting. Olive is the only evergreen tree in the group. I would classify European olive as primarily a 25 to 35 ft. shade tree that can take tremendous abuse. This tree will rebound if pruned badly so it is a relatively safe tree to have if you contract blow and go landscapers to do your property. The other two trees will not rebound like an olive if they are pruned badly. In my opinion, Crape Myrtle might be ruined. If you need something that creates shade, screens, or privacy all year round and is easy on water use, then you might consider olive. As you know we can only plant so-called fruitless olive in Clark County, Nevada. So you will be restricted to either Swan Hill or Wilsonii. However, you can add Monrovia nursery’s Majestic Beauty (Monher variety) to the fruitless list as well. I have had numerous complaints about fruitless varieties producing fruit as they get older. It is believed this happens because these are grafted varieties and the top is lost at the bud union. The rootstock continues growing which is a fruitful olive and the tree becomes an olive tree that produces fruit with a fruitless tag. Others believe tags are mixed up in the nursery. Crape myrtle trunk, young tree In any case, don’t expect your fruitless olive to be totally fruitless. If you need this tree to be totally fruitless, pick something else. Olive is relatively pest free. It requires minimal maintenance. Both olive and Crape Myrtle get to be similar in mature size, around 25 to 40 feet. It will do well in a lawn or a rock mulch desert landscape. You would use this tree if you want a rock solid landscape tree that can handle a lot of abuse. Crape Myrtle can also be spelled Crêpe Myrtle. In other parts of the country they come in a wide range of mature sizes ranging from 3 feet tall to 25 feet tall. Their flower color ranges from white to pink’s, to reds, two lavenders. Selection in Las Vegas will be much more limited but shop around. I have been surprised seeing selections in Lowe’s and Home Depot. It is flat-out gorgeous tree if cared for properly. That is the key. European olive It is what we call a specimen tree, a showstopper when in bloom and even in the winter when it is leafless. It is meant to be a focal point for landscape. A larger tree will provide shade as it gets older but it is really meant to stimulate conversations and to draw your eye because it says, “Look at me!” when it is blooming. Olive flowers Crape Myrtle is a beautiful tree when it is blooming but I would argue that the texture of its trunk and its silhouette in winter rivals its flowers. The exfoliating character of the trunk is gorgeous up close. If pruned properly its winter silhouette without leaves can be beautiful as well. The combination of flowers and uniqueness of its trunk and winter silhouette provides year around beauty. This tree needs to be pruned professionally by certified arborists or by a knowledgeable homeowner. You do not want blow and go landscapers to touch this tree! It will require special fertilizer applications including iron. It will do best with wood surface mulches but it can grow in desert landscapes as well. In desert/rock landscapes crape Myrtle will require more care to keep it looking good over the years. There are dwarf varieties 3 to 6 feet tall, semi-dwarf varieties 7 or 8 feet tall, all the way up to full size which is about 25 feet in height. Most sold here are full-sized but shop around and you may get lucky finding other types. Locally I have had complaints that trees were mislabeled and customers received a different flower color from what they expected. The other complaint was how they were planted. Be very careful of companies that advertise free planting. This tree needs to have plenty of soil amendment go into the planting hole at the time of planting. When planting is free, the holes are dug way too small, very little soil amendment is used and the type of soil amendment used his lousy. If I were buying a boxed, specimen Crape Myrtle I would want to see that the flower color matched the nursery tag and I would have the hole dug to my specifications by an outside party and buy my soil amendment separately from the plant purchase. I would be placing this near a patio, a sitting area outside the master bedroom, near a place for people congregate in the backyard, or where you want people to look in the front yard. It has few pest problems. Vitex or Chaste tree is a smaller tree than the other two. None of the three trees are trees that originate from deserts. However, all three will perform in a desert landscape reasonably

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Chaste Tree with Black Unhealthy Appearance on Trunk

Q. I have two chaste trees in my back yard and for a couple of years now there is a black appearance taking over the trees.   It started at the root or base of the trees and has been traveling up the tree onto the branches.  It is a slow process but somehow this does not seem to be a healthy appearance to me – it looks like black soot although i have not touched it with my hands.  I have asked several people about this and they say the trees are getting old – but i have only had them for about six years and they are maybe 9 or 10 feet, small trees. Can you tell me what to do about this? A. I have not yet seen any disease or insect problems on chaste tree here in our climate and a quick look on the internet I have not seen any reports from reliable sources. This observation is a new one for me.            Vitex winter form. Aphids have been reported to be a problem on chaste trees in other places. If aphids are present you would see them in the spring and fall. Leaves might be cup-shaped due to their feeding.             Excretions from aphids are full of sugar and will cause a blackening of limbs and leaves due to a black mold that grows on the sugar. Even though extracts from seeds of related trees have been reported to kill aphids. I will take a closer look at some here in town and see if I see anything but so far I would have to agree with others. This is a good small tree for the desert with few pest problems except when people water it too often.             If there are no signs of the tree being sick other than this black soot on the trunk, I would guess it is natural aging of the trunk. We do see this type of thing happening on other trees as well.             Diseases like sooty canker you would see a decline in the tree, bark splitting or cracking and the “soot” (under cracked bark) would rub off on your fingers exactly like heavy soot from an active chimney. Sooty canker disease has black spores just under the bark that rub off on your finger like chimney soot.

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