Garden Notes

'Woods Blue' aster with red dahlias
Colorful fall garden combo of 'Woods Blue' aster with red dahlias. Photo by Susan Safford

Advice for fall gardeners

By Abigail Higgins - September 27, 2007

The Martha's Vineyard Agricultural Society will host the annual Harvest Festival on Saturday, September 29, with activities at the fairgrounds free of charge from noon on, and a potluck supper that starts at 6 pm. Please bring a dish made of the best from your garden, enough for six in addition to yourselves. Bring your dancing shoes too. Music is by the swinging Blue Strangers!

Here it is, officially fall, with celebrations, festivals, moonlight, weddings, and travel, all of which are benefited by beautiful weather. For my part though, I find myself wishing for rain and, more and more, a good early killing frost - one that puts paid to the gardens for this year, once and for all. Each year it seems that the warm weather lumbers on and on. Perennials grow, in an uncertain way, and do not begin their shutting-down processes. Weeds continue to flourish, no matter what.

It also makes for a confusing situation if one is contemplating a planting project. Fall is a great time for planting, with temperatures cooling down and rain. We wonder, just how long, how far, in terms of scheduling, can we push the limits, here on the Vineyard?

Fall planting

The October issue of The Avant Gardener reports on "Planting by Degrees," the results of a study undertaken by Cornell University, which supplies good answers to that question. Plantings on Long Island of a variety of specimens were made on the 21st day of each month from August through November.

After follow-up evaluations of the plants in subsequent years, it was observed that the November plantings made little or no root growth and suffered "significant to considerable winter injury, with reduced size and quality still evident two years later." The study's conclusion is that the last safe planting date is about four weeks before the soil temperature, taken six inches down, falls to the 40 F degree point where root formation is halted.

The aftermath of planting - it really should be considered the second stage - is laying down a good mulch layer of compost or composted woodchips, whether you plan to water or especially if you cannot. I prefer layers three to four inches deep, but some authorities recommend mulching to a depth of six to eight inches. Keep mulches well away from the stem or trunk of the plant.

It is always possible (alarming thought) that the fall rains are tardy or scanty. Composted mulches are hydroscopic, meaning that they attract airborne humidity, and are moist inside whether or not they have been watered, which is not the case with every mulch product.

When I was at Sylvan Nursery recently, I asked the knowledgeable Bess Coughlin in sales what she thought the most exciting plants on the premises were. I am contemplating a little project for our own place, one that includes the desired oakleaf hydrangeas I mentioned way back in the early part of the year. I was delighted to hear that Hydrangea quercifolia 'Snowflake' makes her heart go pitter-patter and that they have a few. She also mentioned the Davidias and Parrotias at the nursery. In addition, I added Cornus alternifolia, Corylopsis pauciflora, hellebores, anemones and ferns to the plant list for the project, which is to be planted alongside the path between our house and guesthouse.

We have had a generally good year in the vegetable garden though not enough heat for okra to do well. The one thing I have disliked was having an infestation of whitefly; it must have something to do with the very dry conditions. I sprayed for it with insecticidal soap, which knocks them back but not out. It is the vast clouds of them, inhaled whether picking beans or sunflowers, not to mention the sooty mold on tomatoes and zucchini from the honeydew, which have so offended me. The whitefly is even on weeds!

In clients' gardens we are cutting back and cleaning up where we can, staking or re-staking dahlias and tall-growing Michaelmas daisies (formerly Aster spp. now Symphyotrichum and Eurybia,) and adding mulch and amendments like gypsum, which supplies calcium without raising the soil pH, and endows plants with greater salt resistance and tolerance.

Rebalance and add

It is the time of year to do some "real" gardening: assessing what you like or don't like and taking steps to effect the needed changes. This usually involves huffing and puffing: digging, dividing, and replanting.

We recently moved a beautiful, established planting of painted fern (Athyrium nipponicum 'Pictum') out from behind shrubs that had grown and obscured the ferns, to another location where they can be seen and enjoyed. Every garden has such situations. They are actually the symbols of success: something has survived and grown, and done very well. Now the original picture has become unbalanced and it is the gardener's work to rebalance it.

Divide and reset iris, astilbe, and peonies now. Give the peonies and astilbes a shovelful of compost in the hole, but not so the iris. Eliminate the portions of phlox plants that have changed their bloom from the original by lifting the crown, ripping out the undesirable part, dividing into smaller pieces with about three or four stems apiece, and cutting back to three or four inches. Replant these heavy feeders in nice compost.

Conventional rose advice is to taper off feeding them so they have a chance to harden the new growth before cold weather. However, here on the Vineyard roses are known to bloom beyond Thanksgiving, and I think it is okay to continue to sidedress with low number organic fertilizer or bagged manure through Columbus Day, unless you garden in a frost pocket.

If you garden in a frost pocket the end may be near; many such gardens are frosted every year before the end of September. One might be envious, having the rest of us soldiering on in the gloom of diminishing daylight until mid-November; it might be tempting to extend the season of the garden with floating row covers, especially on vegetable gardens. But if gardens are killed off early, turn lemons into lemonade and clear away, clean up, and start the cycle of improving the soil for next year.

One of the joys of fall gardening is the planning and planting of bulbs. The catalogues are wonderful eye candy, tempting splashes of color, but remember also to dig and divide what was planted in past seasons, for they too were an investment, one that continues to grow.

Attention poultry growers: sometime in October, at a date to be announced, the Island Grown Initiative and M.V. Agricultural Society plan to present a demonstration of the mobile poultry processing unit at the West Tisbury fairgrounds.