Xtremehorticulture

Xtremehorticulture of the Desert

Roses With Strong Growth Needs to be Controlled

2 Comments / pruning roses, remove or not, strong shoot, vigorous growth from roses /

Q. Last fall I planted five rose bushes and they appear to being doing well. Three of the bushes have one large stem growing from the middle of the bush. Should I cut the large stems back to make the bushes more symmetric? A. Very strong growth from plants grafted to rootstocks is frequently a sign the rootstock has sent up a sucker. This type of growth must be removed or it will dominate the plant and squelch the growth from the good part of the plant.             Trace this growth back to its origin and identify where the union is located between the rootstock and the top of the plant that we value for the flowers. Remove this type of growth without leaving any stubs.             The union should be a swollen part of the plant that may resemble, in looks, like a gall or tumor but it is not. If this strong growth is coming from this spot or below it, remove it as close to the parent plant as possible.             The cut does not have to be sanitized but your pruning shears should be and be careful not to let your shears touch the soil before cutting. You can transmit some problems from the soil to the plant on your shears through the open wound.

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White Flowers from Purple Locust Tree?

1 Comment / purple robe locust, white flowers from purple locust, why white flowers /

Q. We had a beautiful purple locust in our back yard that produced a profusion of purple flowers every spring until it was called to locust heaven. Before departing this world it sent off a runner which has sprouted into a lovely tree that is now eleven feet tall and producing white flowers. What’s with that? A. I am making a lot of assumptions in answering this. I am assuming what you are seeing is a locust and not some other plant that happened to grow in that location. I am also assuming the flower looks exactly the same as the purple one, just that it is white.             If both of these are correct then you are seeing the rootstock suckering. The rootstock used for producing the locust with purple flowers is a black locust. Black locust has white flowers but otherwise looks identical to the purple locust.             Oftentimes the locust that has purple flowers is grafted onto a black locust rootstock. The purple part of the plant dies. Suckers grow from the roots of the black locust rootstock and have white flowers.

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Queen Palm Damaged From Irrigation Problem

Leave a Comment / drought queen palm, lack of water, queen palm brown /

Q. During the excessive hot spell our irrigation failed while we were out of town. As a result, one of our queen palms lost all its branches. In spite of subsequent life support efforts it does not appear to be coming back. Is that too much to hope for? Is there anything we can do to help it recover or should we just mourn its passing? If so, what do you recommend we replace it with that has similar height and shade? The remaining queen palms will be wrapped for winter to keep them alive. A. They can normally handle the heat but if they are stressed, and that will happen to that plant in this environment, this could contribute to decline enough so that other factors take over and cause its death. I am sure it was not from the heat directly, but perhaps indirectly when we take into account other things that can be problems. I know it is too late for you but I would generally not recommend queen palms for our Valley. They just end up looking very anemic except in some very protected locations away from hot dry winds. If you are looking for something erect than you might look more closely at date palms Canary Island date palms. They are slow growing but can give some shade. Normally you should not have to wrap queen palms here. Wrapping the trunk may not give you a lot of protection. The central bud at the very top of the tree where the fronds come from is a major determinant if the tree will survive. If that central bud at the top of the tree dies, the palm dies. The trunk can handle a little bit of damage but not the central bud. Some people claim that putting Christmas tree lights around the trunk help some plants. I have never verified this.

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Month Old Gardenias Dying

1 Comment / Uncategorized /

Q. I planted about 12 gardenias a month ago and if them appear to be dying. I checked the soil and it’s evenly damp. It has two 2gph emitters and they are all being watered 3x a week for 20 minutes right now. A. From the picture it looks like a lack of water. Just before you tell me “no”, I want to explain something. A lack of water to the plant can be for many reasons and only one of those reasons is that not enough water is being applied. Follow me on this. Water is applied to the soil. The water fills all the spaces between soil particles forcing the air which is in the soil to exit. As this water drains or is being used by the plant, outside air above the soil begins to enter into the soil filling the spaces that was previously filled with water.  Roots of plants need oxygen. The above ground, green portions of the plant need carbon dioxide and oxygen. If the soil particles are too close together there will not be enough room to provide the oxygen needed by the roots. This is why we add compost and other organic material to the soil so that we can build the structure of the soil to provide that oxygen needed by the roots. I know you have improved that soil for those gardenias so that is not the problem. There is another problem that can occur which can keep water from moving from the soil to the roots and finally to the leaves and stems. If there is something which is choking the stem of the plant, this can prevent water moving from the roots to the leaves. Mechanical injury to the stem from insects which chew or bore holes into the central stem can disrupt water moving from the roots to the top.  There is also a disease problem which can choke the stem near the soil level. This can happen on very young plants which have stems surrounded by wet mulch. If this mulch stays wet around these young stems, it can cause a rotting to occur at the soil to the level of the mulch. This is frequently called collar rot. Make sure that wet mulch does not come in contact with the trunk or stems of young plants. Young plants are very susceptible to this problem. As they get older and developed more wood around the trunk or stems, this problem lessens. So from judging just from the pictures to me it looks like water related and/or too much shade. Excessive shade can cause thin, spindly growth that can’t support itself. That is my best shot at it from the pictures.

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Should I Remove Immature Fruit From My Orange Tree?

Leave a Comment / removing fruit, thinning citrus /

Q. I have an orange tree I planted nine years ago.  It is about 4 feet high and only produced about 2 oranges a year.  Last winter it did have some freeze damage. I trimmed and fertilized it with iron and nitrogen and watered it once a week with a hose instead of the drip system. It is looking real good and has about 40 pea sized oranges on it.  Should I cull some of them as I don’t think the tree can handle that many? A. Normally citrus fruit is not thinned. I wouldn’t take any off. At nine years of age it should be able to handle a lot of fruit. If you think the tree is abnormally small and can’t handle the fruit then remove some but at nine years of age you should not need to.

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Boxwood Hedge Slower to Recover From Pruning Damage Than Rosemary

Leave a Comment / bare wood, boxwood, hedge pruning, hedge shears, pruning, repair, rosemary /

Q. I have a neighbor concerned about his rosemary and boxwood hedges. The foliage has been falling off. Landscapers recommend he cut them to the ground to get them to recover but he opted to cut them back halfway instead. Now there is a lot of bare wood exposed with no leaves. What should he do to help them recover? A. When plants are continuously pruned with a hedge shears it causes them to get thick and bushy.             This increases their leaf density on the outer edges of the hedge. This causes the interior of the hedge to become very dark and the stems on the inside of the hedge to drop their leaves.             They also drop their leaves because the wood on the inside is old. All the new growth occurs where the hedge is being cut over and over. So perhaps only an inch or two along the outer surface of the hedge has leaves.             If we cut the hedge back more than a couple of inches, we expose the older wood that has no leaves. The wood is alive, but without leaves. Once this interior wood begins to receive sunlight again, new growth will sprout from this older wood.             The rate of growth from this older wood depends on the plant. Rosemary grows faster than boxwood. If he is patient, he will eventually start to see new growth coming from the older wood. Boxwood will also have new growth but will fill in slower than rosemary.             If he is patient both hedges will eventually slowly fill back in but boxwood will be much slower. In cases like these most people do not want to look at an ugly the hedge for the next few years and would elect to replace the damaged plants.             Once plants are cut with hedge shears for a few years over and over they are very difficult to reestablish again as plants that are not shaped like a hedge.

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Bamboo Can Be Cut Back to Repair Winter Damage

Leave a Comment / brown leaves, cold damage, freezing damage, iron, repair bamboo, yellowing /

Q. I have bamboo that was damaged last winter as you can see from my pictures. New growth is emerging from them but they are still yellow and brown. Should I fertilize them or give them iron? A. If the plant is still brown from winter damage and the growth is yellow, the only way to really make them look good again is to cut them down and let them regrow from the base. This kind of damage is never going to recover from unsightliness without some regrowth.             I assume this is a running bamboo like golden bamboo. They should come back if they are cut back to the ground but this is not the ideal time to do it. Prune cautiously this time of year.              It would be okay to cut back the largest ones now but leave younger ones until you saw some good solid growth again from the base. Once you see healthy growth, go ahead and cut more back. Otherwise wait until next spring which would be ideal.             Fertilizer and iron will be helpful as it is growing back.

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Have You Pinched Your Grapes Lately?

2 Comments / get larger grapes, grapes too small /

Have you pinched your grapes lately? The berries of table grapes will get much larger if you will remove the bottom third of the bunch. A bunch of grapes has the natural shape of a triangle. Removal of the bottom part of that triangle results in a bunch that is relatively round. If you remove other smaller bunches close by the pinched bunch, the berries will get even larger. You want bunches of table grapes spaced about 12 to 18 inches apart along the vine.

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Vitex Water Management Affects Blooms and Growth

14 Comments / drought, lack of water, no flowers, thin canopy, too much water, vitex /

Q. I have a Chaste tree that has been growing in my backyard for about seven years.  The branches have always been full of leaves and I would get an abundance of beautiful purple blooms. Last spring, I noticed there were not as many leaves and I would only get purple flowers here and there. This spring again the leaves are sparse and the branches are mostly bare. Should I be doing something extra to bring back the lushness of my Chaste tree? A. Vitex, or chaste tree, is relatively pest free. It originates from the Mediterranean region where the summers are usually hot and dry and the winters cool to cold and wet. Vitex in winter             The only real problems the plant has are if the roots remain too wet or the plant doesn’t get enough water. So my reaction to your question was concern about your irrigation practices; either watering it too often or not giving it enough water when you do irrigate.             Both could cause similar problems. If the roots stay too wet, root rots develop and you might see a thinning of the canopy and branches dying back. Watering too often results in poor growth or worse. If overwatering continues, you would probably see dieback in the tree and eventual death from root rots.             If the plant does not receive enough water, the plant canopy will begin to thin out and along with that a reduction in blooms.  If you feel like this tree does not get much water then try flooding the area around the tree once a week in conjunction with your irrigations. If the problem is not enough water, you should see a reaction to additional applied water in 3 to 4 weeks. Vitex in bloom             It also will do best with irrigations similar to other most of your landscape or fruit trees. This means regular deep irrigations.             Avoid daily irrigations. Water about twice a week during the hot summer months. In the spring and fall months, water deeply and thoroughly once in a week. As temperatures cool towards winter, you would probably irrigate deeply every 10 to 14 days.

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Redwood and Cedar Mulches Last Longer in Landscapes

Leave a Comment / cedar, mulch toxicity, redwood, stunt plants /

Q. Would you please tell me what type of mulch is not recommended to put in flower beds? I thought I remembered it being redwood mulch but I can’t find anything on that. Could it have been cedar?  My landscape guy says the shredded cedar is not a problem for vegetation. A. Actually either one will work just fine. Redwood and cedar mulches don’t decompose as quickly as pine and they are usually prettier.             Both cedar and redwood have phenols that help the wood resist decay by fungi and bacteria. There doesn’t seem to be a problem for bedding plants.             My preference is a variety of mixed woods but we do break down fairly quickly (two to three years) and must be replaced.             Many homeowners like the look of redwood and cedar mulches. They don’t break down as fast and so they last longer in the landscape. They may be more expensive initially but they don’t need to be replaced as often as pine mulches.

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