One of the design tactics that has bothered me the most over the years (I know, I know, it’s all about the complaining) is packing a plan full of plants. Sure, the planting looks fantastic for the first few years, but then it soon becomes an overgrown mass of festering evil sprawling over the front lawn. I’ve seen a design chock full of evergreen azaleas, boxwood, a weeping cherry, and various broad leaved rhododendrons. It looked great on paper and was probably spectacular the first few years. The cherry, however, was planted only about 10’ off the corner of the house. The azaleas were packed in extremely close to one another. The boxwood flanked the front door and the rhododendrons were beneath the living room windows. Unfortunately, it had disaster written all over it.
It is extremely important when designing to plan with the future in mind. Plants will not stay the same size they are when purchased. Many plants do not approve of heavy pruning and even if they do it often takes a careful hand to cut correctly. The cherry in that design was the Weeping Higan Cherry, Prunus subhirtella Pendula. This tree grows quickly and can reach a height of 30’ and has arching branches that reach outward 30’. I’ve seen mature specimens flanking the entrance to a park and they towered over the entry road. This is not a delicate and small weeping plant; it’s a real bruiser once it gets growing. Years ago, a customer asked me about purchasing one as they wanted it to grow beneath their dining room window. The window was about 5’ off the ground and their intent was to plant the cherry there for birds to perch on. They were totally convinced they’d be able to pull it off. All the while I was envisioning the tree inviting itself in for dinner by crashing through the window.
The fun doesn’t stop with the weeping cherry in that plan, however. The azaleas in the design would eventually be shaded out by the cherry if they didn’t grow into each other prior. Boxwood, Buxus sempervirens in this case, although easy to prune and shape, does require this maintenance yearly if planted next to a doorway. Further, Common Boxwood has a certain…odor reminiscent of feral male cats. Broad leaved rhododendrons, generally speaking, grow fairly large (8-12’ or more and equally as wide). They’re not a good choice for planting beneath windows (unless a dwarf variety is used which I will mention in a future post).
So, what can a gardener do to avoid a hostile horticultural takeover? First, research your plants. The internet or your local library offer excellent gardening information. Ultimate heights, widths, and growth rates are all obtainable and you should check them out in advance. Thuja occidentalis “Nigra” is a commonly planted arborvitae and often ends up at the corners of a foundation planting. It looks great when it’s small, but what it really wants to do is grow close to a foot each year and reach an eventual height of 30-40’. Not the best choice for a foundation plant unless you’re willing to prune it at least once a year and even then there are better options. Here in New England it’s also a deer magnet and they love to nibble it away to nothing. Knowing the growth habit in advance and some of the plant particulars like attractiveness to deer, can save lots of heartache in the future.
Next, once you’ve researched your plants, make sure they all have more than enough room in your plan. Even with the information you’ve gained, plan some extra space to be on the safe side. Why? Well, plants are much like children; they behave in extremely unexpected ways. Yes, the rhododendron you purchased said it would reach a height of only 5’, but since your location is fantastic it has decided to dominate your foundation planting. Ultimate height and width numbers are guidelines, not numbers written in stone. Your mileage may vary. Watch out for snakes, etc. If there are gaps in the plantings you can always add perennials, bulbs, or even annuals to fill in the space. Be patient and let the plants grow out.
So far I’ve mentioned plants getting too large for a site, is it possible to choose plants that just stay too small? Of course! There’s a homeowner not far from where I live who decided they wanted a living privacy hedge. There are many suitable plants for this task but they went with a double row of Picea glauca ‘Conica.’ This plant is commonly known as the Dwarf Alberta Spruce and its growth rate is measured in amounts of less than an inch per year. The homeowners started off with plants that were maybe 2’ tall. The ultimate height of the tree would probably have made an excellent screening hedge (8-12’). Unfortunately it would have taken decades for them to reach this height. Eventually, they decided to put up a fence. Researching before planting is so very important.
Need some resources to start researching? Sure!
1. Any book by Michael Dirr. I still have an old hardcover copy of his book, Manual of Woody Landscape Plants: Their Identification, Ornamental Characteristics, Culture, Propagation and Use. His works are pretty much the go-to resources for shrubs and trees.
2. Any of the Taylor’s Gardening Guides. There are many of them and they’re great resources for basic plant information including everything from annuals to trees.
3. Garden magazines including Horticulture, Fine Gardening or the BBC publication Gardens Illustrated all have information on plants and design. Gardens Illustrated is a particular favorite of mine due to the excellent photography.
4. http://davesgarden.com has tons of information about plants, gardening, and reliable resources for plants.
5. Check your local botanic garden website. Tower Hill Botanic Gardens here in Massachusetts, for example, has a horticultural hotline you can call on Wednesdays from 2-4pm. They also have many resources on site at the garden. If you’re into native plants, check out The Garden in the Woods which is located in Framingham, Massachusetts. The Costal Maine Botanical Gardens is another fantastic resource if you’re planning a trip to Boothbay and/or midcoast Maine.
These are all resources I rely on constantly as even though I’ve worked with plants for many years, there are always new things to learn.
Asarum europaeum or European Wild Ginger. This fantastic little perennial works well in shady locations. It fills in slowly, more or less ambling across the ground. The dark shiny leaves look fantastic throughout the growing season and it encounters few diseases or pests. I’ve read that it prefers moist soil, but I’ve had it grow quite well in a dry spot with a little extra water to get it established. If you’re looking for a slow growing perennial for near a walkway or as a companion plant to other slower growing shade plants, this is an excellent choice. Note: In no way is this plant related to the culinary ginger—that plant prefers tropical growing conditions.