The high point of the garden year is already over: the summer solstice. Do not worry about it; There is still work to be done, although the Solstice energy reminds gardeners that everything on earth is light controlled: plants, gardens and ourselves. And now summer is here!
The hay harvested from the island’s fields is “stored summer sun”: solar energy that livestock can convert into fats and proteins. We benefit from this because humans are not grazers.
Watch out for boxwood
In the back of my truck in a garden center parking lot, a pleasant exchange took place with a gardener. She asked me if I would be interested in another project and while I turned down another project I asked her to tell me what the problem was. She described a problem with established box trees in her garden, including one that had died over the winter.
Anyone who has boxwood in their garden is usually very attached to it. These slow-growing, perennial plants add a timeless – even mysterious – element to gardens, where they often form a crucial part of horticultural architecture.
Without actually inspecting the plants, it was unwise of me to draw any conclusions; and so I tried to give some general information that might help in finding a solution. I repeat it here because boxwood is now facing several problems in our area.
First, I’ve met numerous people over the years, including people in the business, who refer to “box trees” (Buxus spp.) which were actually Japanese holly (Ilex)! Confirm that the plants in question are indeed Buxus.
(Several Japanese holly, including I. crenata and I. crenata ‘Hetzii’, bear a resemblance to Buxus, and are indeed commonly used today to replace it when boxwood diseases have caused a problem in their use. Nevertheless, Japanese holly has its own number of possible problems.)
Disease problems with boxwood – and there are several, fungi and bacteria – have both environmental and situational causes. A laboratory analysis is necessary to uncover the clear pathogen. While many plants are hardy and undemanding, modern landscape practice has imposed problems.
Many longtime islanders are familiar with venerable island homes guarded by a row of equally venerable box trees flanking the entrance courtyard: sturdy, unkempt, and seemingly aged. Let the place change hands or come under the care of a mowing team and irrigation and problems can arise.
The root systems of the box trees that we usually plant here are fine and close to the surface. Locations with poorly draining soil, irrigation heads, or downspouts can cause problems. I had this at my home: Dwarf box trees that had been in place for 25 years were beginning to fail after a winter of unusually heavy downpours. They found themselves next to a downspout and essentially began to drown. I had to cut out two inch thick wood to save the plants. They still look like amputees (Boxwood is tough and wants to survive!), but otherwise they’re fine.
Boxwoods in lawns are susceptible to damage from string trimmers; I’ve seen this in several gardens. When clipped (actually a no-go with the increasing incidence of box blight) rather than plucked, a layer of dense foliage forms, like an armor, that doesn’t let air or light into the plant’s interior. Debris and dead leaves build up and get trapped inside the plant, promoting (startling?) the potential for disease. In addition, any cut leaf surface is an entry point for disease and a source of stress for the plant.
Just today, while working in a garden with both older and newer boxes, I noticed one whose outline had a broken apart appearance. I looked in and didn’t like what I saw: wet looking and discolored leaves. This plant had to be thinned out immediately. I cut out handfuls of 7 inch sections to allow more light and air into the interior of the plant and will keep an eye on that.
These two links to Virginia Cooperative Extension PDFs (bit.ly/VABoxwoodInfo)
and Saunders brothers (bit.ly/SBonBoxwoods), give you almost everything you need to know about boxwood cultivation. I recommend going through them to learn everything you need to know to keep the box in the garden healthy for years to come because these are truly lifelong plants.
In the garden
Now is the time to top, prune or shape early and spring flowering shrubs. These include the very early, lemon-scented Lonicera fragrantissima, viburnum, weigela, rhododendron and azalea, spirea and kolkwitzia.
The spring bloomers form their blossoms on wood from the previous year. If care is taken now, next spring there will be no loss of flowers. Since becoming aware of the widespread damage done to island lilac by the lilac borer, I now limit lilac pruning to removing seed heads, not wood, which is larger. Lilac borers use the smell of cut wood to find places to lay their larvae’s eggs. Save shaping and removing old wood for later in the season.
Keeping the vegetables going is a challenge when heat and drought hit. Leaf lettuce is proving to be particularly susceptible to heat as we head into the hotter part of summer. Small reseeding of lettuce, beans, spinach, radishes and other fast-growing plants makes the most sense. Extend the pea harvest by leaving the pea pods picked.
Crabgrass is popping up, particularly troublesome in lawns and in peastone and beds. Likewise, seedlings from various biennials and pollinator-friendly garden plants. If she overseeds prolifically, she is a pollinator friendly plant! Examples: Verbena bonariensis; several members of the spurge family, butterfly weed (Asclepias tuberosa) and marsh spurge (A. incarnata); cilantro and arugula in vegetable gardens; and thimble. You need to decide what to keep, discard, or move. Remember, next year’s inexpensive, low-effort flowering plants are this year’s seedlings.