As I mentioned back in June, it's become clear to us that one of the biggest time-sinks in our current yard is that massive forsythia hedge on the north side of the back yard. The bushes are too big and too close together, and they seem to require constant pruning to keep them from ensnaring our clothesline. If we don't want to spend every weekend out there with the pruning shears, we're going to need to replace them with something smaller and more manageable. However, Brian definitely wants to have some sort of hedge there to shield us from our neighbor's yard (which is somewhat untidy and often noisy). So we're looking for something that gets about three feet tall, doesn't spread too far, grows well in clay soil (so that we don't have to amend the dickens out of it before planting), and also looks reasonably nice. Ideally, we'd also like to plant something on the surface of the slope to keep the weeds down, so that Brian doesn't have to beat them back periodically with the string trimmer.
Now, one shrub that shows up consistently on lists of the best plants for clay soil is Potentilla fruticosa—also known as shrubby or bush cinquefoil. It grows to about 3 feet tall and correspondingly wide, it's suited to our climate, it can grow in full sun or partial shade, it grows fine in clay soil, and it produces nice flowers that attract butterflies. Most varieties have yellow flowers, but I've also seen pink and white versions. I'd actually considered planting some of these as foundation shrubs in the front yard, to replace some of the massive evergreen bushes we have now, but I hesitated because I wondered whether we'd be better off with something that stayed green through the winter or otherwise could perk up the drab winter landscape. Now I'm thinking perhaps this spot in the back yard is a better place for them.
Then, for the slope itself, I was thinking of some sort of cotoneaster. It stays low to the ground, yet spreads out to about six feet wide, and it requires very little maintenance—in fact, the site I linked to says it looks best if you don't prune it at all, except to remove dead or damaged branches. They can also handle clay soil and are often recommended specifically for controlling erosion on slopes. One particular variety that looks nice is bearberry cotoneaster, which is semi-evergreen, has nice fall color, and produces cheery red berries that will linger into the winter. These are also said to make good food for birds.
So, it sounds like these two plants should make a nice pairing for this problem spot, right? So what's the problem?
Well, the problem is that I've been working, bit by bit, on transforming our yard into an edible landscape—and so I hesitate to add anything new to the landscape that isn't edible. Yes, the bush cinquefoil and bearberry cotoneaster would provide other benefits—flowers throughout the spring and summer, bright berries in fall and winter, food for the birds—but even so, replacing one non-edible plant with another just feels like a missed opportunity. It seems like there must be something I could put on this slope that would serve as a privacy screen and an erosion control and provide food at the same time. But is there?
I posed this question in a thread about edible landscaping on the Dollar Stretcher forums, and I got a variety of suggestions, including gooseberries, black currants, honeyberry (a variety of honeysuckle with edible berries), sweet potatoes, "dwarf fruit trees," and elderberries. However, looking into these options, it seemed that most of them were too tall for the site. Since we'd be planting on top of a slope that's already three or four feet high, anything much taller than three feet would be impossible to harvest without the aid of a ladder. The honeyberries were an intriguing idea, one that I'd never actually heard of before, but there don't seem to be any varieties shorter than 4-5 feet tall. Elderberries, likewise, are at least 5 feet high and spread even wider, so we'd have the same trouble keeping them trimmed back as we have now with the forsythias. Gooseberry and black currant bushes appear to be only a little bit too large (3 to 6 feet), but they require selective pruning—keeping track of how old each individual cane is, and cutting out the oldest ones each spring—which sounds like a huge hassle. Also, The Weekend Garden Guide by Susan Roth, my personal landscaping bible, warns that these species can harbor a disease called white pine blister rust, which can threaten native pine trees (like the huge ones outside the apartment complex just down the block from us).
Searching for other ides, I consulted a handy site I discovered called Temperate Climate Permaculture. There were several plants I hadn't heard of before listed under "shrub layer" and "groundcover layer," including salal ("an evergreen understory shrub" with "sweet, great-tasting berries that are reminiscent of blueberries"), creeping blueberry, and relatives of the blueberry such as huckleberry and bilberry, but upon investigation, none of these appeared to be a practical choice for this particular site. The only option on his list was a low-growing variety of juniper, and these plants are only "edible" by the broadest possible definition (the berries are used as a flavoring agent). There are also groundcover roses that produce edible hips, but frankly, I look on these as more of a novelty than a viable food crop.
So there's my dilemma: should I just go with the two plants that fit the site, even though they won't expand our edible landscape? Or should I continue looking for edible options? Fortunately, we probably won't be able to buy new plants for this site until spring, so I have several months to think it over. But I don't want to spend the whole winter scouring the Internet for an ideal edible plant that may not actually exist.