High Density Planting for Fruit Trees

I recently received several different cultivars of cherry that I wanted to introduce to our orchard. But as you can see, it's getting rather full. And this is a problem many homeowners face. They want to grow a variety of nutritious fruits, but don't have a lot of room for those. So one way to overcome this problem is to use a high-density planting system. And this is an example of that with my cherry trees. In a high-density system, one way we could do this is by planting two to up to four trees in a single planting hole. And we space the individual trees fairly close. They're about 18 to 20 inches on center, so we have a greater variety of fruit growing in a very small area. Another example of a high-density planting scheme would be to plant your fruit trees in a hedgerow system, much like how we have our blackberries planted. You would put the individual trees on two to three-foot centers, and eventually you'd have a living wall and an edible wall surrounding your landscape. The final high-density system that we're most familiar with would be an espalier structure, where we have a tree pruned so that it can grow in a very small space. Now obviously, this is much closer plant spacing than what we normally recommend when we're planting fruit trees. And you certainly wouldn't see this in a commercial orchard. But homeowners often have different needs, certainly different equipment and different labor than what we find in the commercial orchard. And so this system can offer us several advantages. Now the production per tree is going to be lower, because these three trees are close together and they're competing for all the nutrients and sunlight, water. But if you look at the production per area, we're not going to lose too much in terms of fruit production. We're certainly going to have enough to feed a household. This system does, however, offer several advantages. Now many of our fruit trees, like our plum tree here, require pollinators so that they have good fruit set. And if you have a small space available to devote to fruit trees, you might not have room for a pair of plum trees for that good pollination. With high-density planting, we could put the two trees in one hole, and they're right side by side, so we're going to get really good pollination. We can, of course, also plant multiple cultivars, so we don't have to make that difficult decision between the bean cherry or the rainier. But we can even plant closely related fruits together. For example, plums and nectarines, apricots and the pluot, which is a hybrid between the plum and the apricot. These all have similar growth habits, and so we can put these together in one hole in a high-density planting scheme. A final advantage would be extending our harvest. A good example would be peaches. We could plant an early ripening, a mid-season, and a late-season peach all together so that we have fruit production for a longer period of time. Now one thing you want to consider if you're planting multiple fruits together is that you select plants with a similar rootstock. We don't want to plant a dwarf plum right next to a peach that's on a standard rootstock because that dwarf plum won't be able to compete as well for water and nutrients. Another goal of most home gardeners is to keep their fruit trees at a manageable size. Now in an orchard, growers typically scale 12-foot ladders to thin or harvest fruit, but homeowners are less likely to do that. We want a small tree that we can easily reach for pruning, for thinning, for harvest. Perhaps we want to cover it with a net during certain times of year. There's several ways that we could keep that tree small. One is through our rootstocks. We talked about this earlier, how some rootstocks have a dwarfing effect. Another is just simply this high-density planting. When we put these plants close together like this, their roots are going to be competing for resources, and so that is going to naturally have a somewhat limiting effect on the size. And we'll also look at some pruning to keep our trees short. We want to have a goal in mind, and that goal is to pick a size for the tree, and through our pruning, keep it that size. And a good size for our fruit trees would be something that we can reach from the ground or from a short step ladder, so somewhere under eight feet that we can easily reach in, harvest, prune, and maintain our plants. Now with all fruit trees that we plant, we begin by cutting the trunk back. It comes from the nursery with a nice branch structure, but you can see these branches are pretty high up off the ground, and as they extend and branch out, we're putting this canopy up here, and all the fruit's already up high. So what we want to do is come in and cut our trunk back, and that's going to cause buds down here, lower on the branch, to open up and send out new shoots that are low. And what'll happen is we'll have a nice, low canopy where we can reach that fruit. Generally, we cut our branches, our trunks back to about knee high, and you can do it a little bit lower than that. I'm going to go ahead with just below my knee, and it seems rather extreme, but we're going to do this for all of our trees, and we'll end up with a nice, low canopy that we can easily maintain. Now these branches are going to start, the buds are going to open, we're going to get some branching coming out, and some of these you can see here are pointed towards the inside of the tree. Those we're going to want to come in and prune out, because we want to keep the center area somewhat open for air flow, but we're going to encourage more outward growing branches as they grow. We'll also want to come back with what we call summer pruning, and that's a technique to keep this dense canopy really small and tight. But it is a lot of work, so it might not be for everybody. With summer pruning, we come in in the spring and we'll remove this new growth by half, and then we'll come back again in the summer and prune it again by half. So it's a really intense pruning method, but it'll produce a nice, tight, dense canopy and keep it low so that we can manage it easily. Now one last thing to consider, if you have several cultivars planted in a high-density system like this, is that one might be more vigorous than the other. For example, I have a Rainier and a Royal Rainier and a Bing Cherry, and the Bing happens to be on a rootstock that's a little less hardy than the other two. It has more of a dwarfing characteristics, and so I positioned this cultivar on the south so that it wouldn't have to compete as much for sunlight, and that might help it compete better with the other two cherries. Another thing, if you do see one cultivar that's just growing more vigorously, it's okay to cut it back a little bit harder than the others.