By Mel Bellar
If you have ever purchased plants at a nursery and read the label, you know that it will inform you as to how far apart to place your new purchase from its neighbors. Many factors come into play when considering how seriously to take this recommendation, but perhaps the most glaring is your patience. I am not a particularly patient person, but I am learning, and usually weigh the other factors involved over my desire for instant gratification.
Besides patience, you need to consider the budget, the type of plants (tree, shrub, perennial, deciduous, evergreen, etc.) and how willing you are to make adjustments as your plants grow in and mature. You can plant a garden to look good immediately or plan for 3 years, 5 years, or for the long haul. It is not possible to have it all without some serious compromise. If you plant to have it look full and lush immediately, you are going to have to take things out and move things around in a few years or your plants will be running together and choking out their neighbors.You also lose the integrity of the plant’s habit or structure. If you plant with the long-term in mind, you will have a lot of space between plants for a quite a while and I, for one, generally don’t like the look of isolated plants surrounded by mulch. This dilemma is one of the main reasons that I stress the need for structure (walls, stone, paths, etc.) in the garden to provide interest even when the plants are small or dormant in the winter.
Let’s start with the big stuff. Planting trees too close together, too close to the house or too close to the power wires is not a good idea. It is sometimes hard to accept that a sugar maple whip (small bare root plant), or even a 12’ ball and burlap purchase is really going to grow to 60’ tall and 30’ wide and eat your house, but it might. Planting deciduous trees close enough to touch or intermingle is OK, considering that nature does it all of the time and they do fine, but if you want that beautiful structure of an unencumbered tree, pay attention to its projected mature size.
Now evergreen conifers, of any size, are another story. They do not play particularly well together. I have some recent personal experience with this. I have a conifer garden that I planted too tightly in the mid 2000’s, packing in as many cool varieties as I could. It looked pretty great for 10 years or so but then they started to grow together, resulting in limited light and reduced air flow. Then, this year we had the dead juniper syndrome that I wrote about in my June column. I had to take out several large junipers and an Alberta spruce. It was like dominoes falling; each evergreen I took out exposed the nasty browned-out areas of the remaining evergreens, resulting in a huge job at great expense. And I still have more to do. The moral of the story is not to plant ornamental conifers too close together unless you want to take them all out and start over at some time in the not too distant future. It actually works the same with larger conifers, but the downside is usually not so obvious unless you lose a tree in a tree fence. A tree fence is a row of conifers planted close together to create a screen. The trees look OK as long as you don’t see the inside where they grow together. If you lose a tree the nasty insides will be exposed, just like in my beautiful
Shrubs, both evergreen and deciduous, have similar considerations. It has taken me a long time to learn to give shrubs the room to be themselves. In years past, I planted a lot of shrubs too close together because I wanted to fill in the space quickly and believed that I could control them with pruning. This is true to some degree, but plants just generally look better and do better if they are not continually pruned to stay within a space that is too small. Although any shrub given its desired space will look great, there are exceptions to this rule: There are types of shrubs that work nicely in masses and blend together well (red twig dogwood, shrub honeysuckle [Diervilla], Annabelle hydrangeas …) and there are shrubs that do well with regular heavy pruning (hydrangeas, spirea, potentilla …). Then there are shrubs that really look better left to their own devices: ninebarks, dappled willows, smoke bush, weigela, rose of Sharon ….
Unlike trees and shrubs, I tend to take the spacing suggestions for perennials with a grain of salt. I like for most perennials to create a nice mass that is dense enough to shade out the weeds. As a homeowner, I like to create masses by putting in smaller plants, closer together than recommended. That way it fills in more quickly and saves a lot of money. I often do this with clients who have less budget than patience. It is one area of landscaping where you can really save some money without compromising anything but the time it takes to fill in. I use cuttings and divisions to make it really easy and inexpensive for many varieties of perennials. There are exceptions where I want perennials with a nice habit to have a specimen-like presence, like peonies or larger specimens like ironweed (Vernonia noveboracensis), cup plants (Silphium perfoliatum) and hibiscus.
Overall, it is best to pay attention to the recommended spacing of plants and plan to wait for your plant to reach its full size. In the case of trees and shrubs, I think it makes sense to fill in between them with annuals, ground covers or perennials that you will remove to give the tree or shrub room as it grows. Alas, gardening is full of life lessons including compromise and making adjustments.
Mel Bellar is the owner of Zone4 Landscapes and a passionate Andes gardener.~