Pine Mulch and Spruce Care

Question:
We bought pine mulch for our front yard but the bag did not indicate that the pine mulch was treated for termites. Is there a prevention agent I can spray on the mulch to kill termites?
Also are there any sprays or treatments to use on my spruce tree to prevent any damage to our lovely 40 ft spruce? Are there any diseases I need to look for or prevent against for spruces?

Answer:
Regarding the mulch, I can relate. I apologize I am not writing sooner because I might suggest returning it if you have seen any signs of termites present. I have the HSNY Librarian, Katherine Powis, searching to see if there is any new information we might be able to share. At this time I do not know of anything that you can treat your mulch with. Supposedly the termite issue in mulch often comes from bags or palettes that sit with excess moisture for lengths of time. The best is to look for a nice dry bag or palette of mulch next time you are shopping. From what I understand the termite mulch issue got significantly worse after Katrina because much of the mulch was coming from down south and exposed to more moisture than not for lengths of time prior to being shipped up north. Even some staff here in our office have been dealing with these issues in their own gardens. We will continue to research and let you know what we come up with.

Regarding your big spruce, simply taking good care of the tree as you have been is the best approach. The older trees get the less they need or like to be coddled. Mature trees should not be fertilized heavily or pruned aggressively because it takes them longer to acclimate to the changes. To minimize stress and encourage a healthy, long-lived tree practice basic proper upkeep. Prune any dead or diseased wood but otherwise keep pruning to a minimum. Feel free to top-dress the soil with an inch of compost or mulch, but do not add more than 2 inches because we want to make sure the roots continue to get enough water and fresh Carbon Dioxide. Try to avoid any compaction of the soil at the base of the tree. If we have extended periods of drought then the tree can tolerate some supplemental water, but by this point it is probably pretty used to "nature's watering schedule". Regularly scout for pest and/or disease issues. The lower and interior branches and needles will fall as the leader and tips of the branches continue to produce new growth. In terms of scouting for pests and diseases, you want to focus your attention more on the new growth and tips. Make sure that you do not see any browning of the needles, holes in the stems, or black fungal spots, or anything that seems blatantly different than the rest of the tree. When it comes to a mature tree like that spruce of yours I hesitate to take any drastic action until we know there is a detrimental situation present.

Browning Evergreens in Containers in Brooklyn

Question:
My husband and I bought two potted evergreen trees in December of 2006 for Christmas and are trying to maintain them on our deck in Brooklyn with little luck. Right after the snow we noticed the trees started to turn brown and loose their needles. One tree lost a lot of needles very rapidly. The other maintained most of its color and most of its needles. Three weeks ago, in order to try and resuscitate the first and prevent further damage to the other, we decided to replant both in slightly larger pots. We have been watering them at least twice a week and adding Liquid Grow Plant Food. It seemed to help during the first two weeks. The tree with the most damage was almost completely brown and then it made a slight come back with some small patches of green...a small victory for us. But presently it hasn't restored fully and stopped improving. The other tree is doing better than its neighbor. It is 95% green. The browning is in patches at the bottom of the tree. They both get the same amount of sun light from the North East and I still water them at least twice a week although these last few days I didn't because of all the rain. Is our little brown tree too far gone to make a come back and what can we do to make sure the same doesn't happen to our other? Any advice you can give us would be much appreciated.

Answer:

What you have in your containers are two dwarf Alberta spruce (Picea glauca ‘Conica’). As you see them all over the city, they are popular ornamental trees for containers because they are slow growing and hold that very formal, conical shape. They require full sun and, especially in a container, supplemental water.

Looking at your pictures, I am sorry to say that the one on the left is not going to come back for you. Of course there are always exceptions in the plant world, but to generalize evergreens do not bounce back as easily as deciduous trees, shrubs, or perennials. For deciduous perennials, trees, and shrubs, there are dormant leaf buds that can sprout and provide foliage even after a plant has been cut back. Evergreens grow from their tips out, and usually do not have the same kind of dormant buds. Some evergreens can be pruned lightly to push out more new growth, but by and large evergreens will not put out new growth on a branch that has already dies back.

Therefore, the tree on the left is not going to bounce back – it is best to simply start over. As far as the one on the right, you can prune off the brown branches at the bottom, because again, they are not likely to needle-out again. Evergreens, again, in general, naturally prune themselves from the bottom up if they are under stress. This is typically a response to not getting enough sun – and I have seen it happen on Alberta spruces plenty. Keep it in as sunny a spot as possible, continue to water regularly, and hopefully you will not loose any more of the needles. Next, look at the tip of the branches. If you have new green foliage emerging from the tips then you can rest assured that the tree is still healthy and going to do well this summer.

As far as what killed the other…? It could have been not enough sun. It could have also been not enough water, because you really have to keep containers irrigated constantly. Lastly, reexamine the space. Sometimes there may be a draft or an exhaust fan that we don’t pay attention to that is drying out a plant and/or container faster than we realize. Without being able to see the space, I would go back to guessing it is mostly a sun issue, and even though it may be bright, sticking a plant in that corner might not be the best option unless you know it to be more shade tolerant.