|Above, in the middle of August, our Red silk tree (Albizzia julibrissin ‘Red Silk’) put on a dis-play that far outweighed anything it had done previously. Although it grows in climates such as New York City (a good street tree) it is not hardy in southern Ontario. Below, in bloom right now is a young Himalayan honeysuckle (Leycesteria formosa) which is a very nice shrub for fall colour, again not hardy in southern Ontario. Author photos. |
Bernie and Fred Burnie wrote on August 14 with this question: “We have an evergreen tree that has turned brown at the top--this condition appears to be progressing down the tree. The trunk as well as any branches are affected. I am unsure of the species of tree (you can see its family growing all over)--it has short flat needles. It is now about six ft. tall. We grew it from a seed and several years ago transplanted it. It is now planted in the front lawn about 13 feet from the road and 10 feet from a birch tree. Across our driveway is a similar tree--a few years older and therefore taller. It does not appear to be affected by this problem. Any suggestions? Should we just trim off the dying part or are we looking at a systemic problem?”
Since there was no indication of where they live, I wrote and asked for that information, and received the following reply: “Thank you for replying Art. We live in Thornhill, ON. I stopped at a nursery last Sunday and spoke to one of the horticulturists there. I showed her a "leaf" from the evergreen--she identified it as a balsam fir. Because of the hot weather we've been having during July and August she felt our tree was dying of thirst (regretfully I must admit we do not water our trees). She recommended watering for an hour 3X a week. We started doing that immediately we arrived home--the browning at the top has not proceeded further down the trunk. There is no indication of any kind of infestation on the tree. We hope the top will "come back" next spring. Thank you for replying to my e-mail. We listen to your spots on AM740.”
While I agreed with the diagnosis they received from the garden centre horticulturist, I thought there were a number of other considerations, and replied as follows.
“How much water the tree had received this summer was going to be my first question once I ascertained your location. However, my understanding about the situation in southern Ontario this year is that there has been above average amounts of rainfall, even though the heat has been strong. Perhaps more important than how much water/rain, is whether or not the natural needle mulch under the tree out to the tips of the branches has remained in place, or if you have trimmed up the lower branches, and consequently thought you should rake away all that poor looking mulch. If that is the case, therein is your problem. That needle mulch must be left in place which in turns holds some moisture for a longer time, and also stops the moisture from evaporating out of the ground during hot weather.
I am certainly not sure that the top of the tree that has browned will “come back” next year. If, as I suspect, it does not, you should trim off the dead portion down to a live bud on the central branch, and begin to train a new central leader from the largest bud on the older (live) part of the leader. That usually involves shortening back all other growths to let the one leader gain dominance. Often it is necessary to tie a thin stake to the old leader and gradually tie the new growth to it so it will continue to grow upright, instead of sideways, which is what it will want to do because it is a side bud.
As regards watering, if the needle mulch is intact then fine, but if not I would add some type of bark mulch to a depth of at least 5-7 cm. If the lower branches have been removed totally and there is grass under the tree, it would be best to convert that to some sort of mulch. Then, I would install a black ‘leaky pipe’ type soaker hose. It should be looped back and forth so the loops are about 60 cm apart. It should be run much as the garden centre instructed.
Hope that helps.”
Madge Veitch from Innisfil Ontario wrote last Friday: “My Hydrangea ‘Limelight’ has been in the ground for 3½ years and flowers amazingly, especially after a shot of Liquid Growth. However the flowers are so large this year it is leaning over onto the ground and I am not sure how to prune. I always leave the dead flowers on until spring and then cut off just under the old bloom. It is leaning to one side but I don’t want to have to tie it to a stake. I am using Liquid Growth this year for the first time and everything has grown bigger and better. Thanks for the Tip.”
‘Limelight’ is one of the newer Hydrangea paniculata types, and these require little pruning. However, if it is leaning, I would certainly prune perhaps up to one-third of the branches that are heavier than the rest of the plant. And, you certainly may prune the flowers off, even now, or slightly later, and bring them in the house to dry, and then use them in a dried arrangement over the winter. As far pruning the plant itself, as I have suggested, I would rather you leave that until early next spring, although it will not likely harm the plant if you do that this fall as well.
I am pleased that the BioTLC Liquid Growth worked as well for you as it does for so many of my radio listeners!
Last week here, I responded to Ray Johnson’s question about white flies in his Cambridge Ontario greenhouse. In addition to that response he later advised that the greenhouse was indeed free-standing, and therefore I suggested he might wish to obtain a can or two of Doktor Doom High Pressure Fumigator and use that initially to rid the greenhouse of some of the white flies.
Audrey from somewhere on Vancouver Island wrote also: “I would like to know how to get rid of a "large" stand of Bamboo in my garden. It has taken over and I would like to get rid of it. Help.”
One thing I don’t think you wish to do is to dig it out Audrey. From experience here, I can tell you that is most difficult. I would try an application or two of Roundup at two or three times the recommended strength (in other words, start with the concentrate). However, there is something else to do first and that is cut/encourage new growth and then paint or spray the Roundup. You may even be able to get rid of it using the cut/encourage new growth/cut again technique and no chemical.
If you cut it down, even now, then be sure to water and fertilize it well. Once the new growth is up 15-20 cm, apply the Roundup either painting it on with a wide paint brush, or spraying on the strong solution you mix up from the concentrate.
You may very well have to do this several times.