I planted a japanese holly about a month ago in the northeast corner of my house. I was watering it pretty regularly but went away for a week. When I watered it today, almost all of the leaves fell of. All I had to do was touch a leaf and it would drop although the leaves were still green and not browned. There are some tiny bud/flowers and the plant looks green. Has it been underwatered? overwatered? underfertilized? not enough sun? I would appreciate any advice.
Oh, and it might help if I told you I live in eastern massachusetts.
A little transplant shock is typical, but this sounds much more severe. If your Japanese holly does not get quite enough sun then it will thin its lower, interior leaves. This interior thinning will also happen as plenty of new growth emerges from the tips of the stems and the plant grows larger. However, all that usually happens over a longer period of time, so I’m a little unsure as to why you are having so much leaf drop so quickly. I guess my mind then goes to other planting or cultural issues. I hope the rootball didn’t suffer too much damage when planted. Whether containerized or balled and burlapped it is important to keep the rootball as in-tact and protected through the planting as possible. You can and want to rough up the roots around the edges a bit to encourage them to grow out and down but never want to put too much pressure on the rest of the root mass. You should have planted the shrub so that it is level with the soil around it. Many used to advise to prep the hole twice as wide and twice as deep as the rootball, but now the consensus is that you do not want to dig too deep because you do not want the plant to settle and then have the crown of the plant below the soil line. If the shrub is planted too deep then you can run the risk of rot and the roots not getting the fresh air that they require. After planting I would “water in” the shrub by putting the hose on a slow trickle and letting it sit and soak the roots for an hour or so. Following that I would water a newly planted Japanese holly two or three times a week early in the day for an hour or two each time. For this, using soaker hoses with a battery operated timer can be a great help and make it easy on you. Regular and evenly spaced watering is a proper horticultural practice I can't talk up enough. If the shrub goes a week without water then obviously water it when you return, but do not then over-compensate and flood the plant. I always make the analogy that if you are dehydrated you do not then try and drink a gallon of water in one sitting, you sip, slowly and over a period of time, and then you will begin to feel normal again. In this respect plants are not all that different from humans. The dehydrated roots will not know what to do with such an excessive watering and you can do harm when you are trying to do good. Again, I might expect some leaf drop, but not like what you have described. And being away for a week should not send a woody shrub like that downhill so fast. On the remaining leaves, examine the undersides of the leaves and the nodes, the junctions where leaves and stems meet, and tell me if you see any sign of insects. Look at the base of the plant and make sure it is not too deep. If so, you might have to pull it out and replant it raised up a bit. For trees and shrubs people will tell you to err on the side of planting too high instead of planting too deep. Also, since this occurred so fast, call the nursery and explain the situation and ask if other people’s new hollies have been suffering too. There might have been something affecting the whole batch that no one had noticed before a bunch of them were sold. As far as winter hardiness, I believe that the holly should hold up where you are living. (Otherwise why would a nursery have sold it to you?). Some references say that they are only hardy to Zone 6 and I bet you might be a bit colder up there, but I am sure I have seen these broadleaf evergreens up that far.
Hmm, very interesting. Of course, if you have a digital camera you can take and email me some pictures and we can see if that helps me diagnose the situation any better. Think through the planting process you underwent and let me know if any other factors may have come into play. I’ll keep thinking too.