Garden Notes
By Abigail Higgins
Published: July 17, 2008
On July 22, Slow Food Martha's Vineyard hosts its annual potluck dinner and fundraiser at Agricultural Hall with the author Michael Pollan as keynote speaker. He is the author of "In Defense of Food" and is one of nation's best-known proponents of eating locally. Please go to slowfoodmarthasvineyard.org/Welcome.html or contact elizabeth.germain@gmail.com for more information.
Catching up in the garden
The weeks are hurtling by and it is mid-July with the full moon nearing. If your garden is tiny do not worry about it, but if possible, develop a rotational plan for the vegetable garden. It is now or never for planting fall crops of carrots, beets, Brussels sprouts, and turnips. Lovers of dill and cilantro want to keep supplies of these crops coming along too. A simplified approach would be to categorize what you grow, for example, root vegetables, greens, and legumes, and just plant something from a different group in place of the first crop: cabbage following peas, or kale following early beets. Another way of grouping plants is by families: the nightshades, Brassicas, and cucurbits. The families share the same diseases and pests, so if possible switch their locations each year too. Think about where you want next year's crops, now.
Hydrangeas: soil pH and making your own
Island hydrangeas are putting on a gorgeous display. This season has rewarded those who have bought, planted, and cared for them. A frequent question is: how does one "blue" hydrangeas, to which there are two answers. On the theoretical level, understand that it is soil pH that causes the plants to color towards the blue or the pink: acidic- low pH for blue, and basic- higher pH for the pink. Color won't manipulate in so-called stable cultivars.
The other, results-oriented, answer, is that purchased aluminum sulphate, ammonium sulphate, or agricultural sulphur can be worked carefully into the soil around the plants in early spring just before growth starts. In my opinion, it is bad practice to add any metals to soils. Toxic compounds of aluminum are implicated in many serious conditions, and metals in soils eventually find their way into the water supply and food chain. Therefore I recommend sticking to leaf mold from oaks, ammonium sulphate, or agricultural sulphur to blue hydrangeas.
Photo by Susan Safford
As gardeners deepen their skills, though, propagating enters the picture. Why not try taking some softwood cuttings? Well-marketed hydrangea cultivars with improved performance have become the superstars of the plant industry, but lots of gardens contain unknown older cultivars of great beauty, which are in danger of being swept into oblivion by the buzz surrounding the superstars. Many shrubs and vines are good subjects for softwood cuttings too, but hydrangeas are easy and a good plant with which to start.
Select shoots without flower buds and cut them cleanly with a sharp blade. Have some six-packs or small pots filled with a quick-draining soil-less mix. Look for shoots that have a couple of places where the leaves grow, called nodes. Remove the leaves from the lower node and cover the node and stem in rooting powder. Insert the cutting gently into a hole in the potting mix that you have made with a pencil and firm the mix around the cutting. Use a mixture with a high percentage of perlite or vermiculite so that the potting mix drains well.
Rig some sort of framework that will support a plastic bag and hold it off the cuttings. Moisten the potting mix and with scissors cut off a portion of each leaf; then place the six-pack or pots inside the plastic bag tent. Close it up but not necessarily totally airtight and place out of direct sunlight in a shaded place. Check the cuttings regularly and mist if necessary, but do not over-water. Hydrangeas often root quite rapidly. Once roots fill the small container, upsize to a larger pot and treat like any young plant.
There is obviously more to the art of propagating but for softwood cuttings that is pretty much it in a nutshell. Most books that instruct the repertoire of basic gardening practices describe taking softwood cuttings too. If you are thinking of buying a work devoted to propagation, I like Ken Druse's book, "Making More Plants" (Clarkson Potter, 2000, 256 ppg) because it is visually beautiful as well as supplied with ample information.
No caterpillars, no butterflies
It is not exactly a caterpillar story, but friends working on a project at our place were amazed on two accounts recently. First, the shop suddenly became filled with lots of large, rusty brick red moths in mating mode. They were followed by normally circumspect catbirds flying into the building and fluttering right past the surprised woodworkers' heads to pursue and gobble up the large numbers of mating moths. When I came home from work I found a few remnant moths on a windowpane and recognized them as Saturniids, Anisota senatoria, the adult form of the black and orange striped oakworm. It seemed as if the catbirds, likely feeding nestlings, were primed and waiting for this seemingly fortuitous windfall feast.
Is the parsley disappearing before your eyes? Chances are that caterpillars of swallowtail butterfly are feeding on it. These caterpillars prefer parsley, dill and other umbellifers of the carrot family. Are silver-foliaged container plants (curry plant or licorice vine) exhibiting webbing filled with dark hairy - ugh! - caterpillars?
While caterpillars on ornamentals can be controlled with Bacillus thuringiensis, (Bt) please refrain, and make an effort to identify the caterpillar. Then perhaps plant a little extra - as there are no butterflies without caterpillars first. The dark hairy caterpillar with the preference for grey, felty foliage is probably the larval form of the beautiful little black and orange spotted American Lady, Vanessa virginiensis; and the striking black, white, and chartreuse stripy caterpillar becomes the large yellow-spotted black swallowtail, Papilio polyxenes, a joy to behold as it floats about the garden. (With thanks to Matt Pelikan for species confirmation.)
Editor's Note: In the July 3 Garden Notes column, the word axillary was changed to auxiliary during the editing process.
