Garden Notes: Poison sumac

Some sumacs are poisonous, some are not.

Poison sumac: Brilliant fall color, wetland location, and dangling bunches of white berries are characteristics. —Susan Safford

Poison ivy, poison sumac, poison oak! These are the feared plants that visitors to the Vineyard want to know about. Only the first two are known to occur here, according to “Flora of Martha’s Vineyard,” but the threesome is often shrouded in schoolyard exaggeration and fear-mongering, or the cocky bravado of those who are immune.

Misinformation abounds. Such is the reputation of these poisonous plants that people want to be well forewarned if any are nearby. We arrived to work at a garden last week, where the owner’s visiting parents were worried about a large sumac near the house: Was it poison sumac?

Although I have looked “at” poison sumac many times as background vegetation, I had never consciously “seen” it. As it happened, I had just seen and identified poison sumac, with the help of Polly Hill Arboretum. I had timely knowledge to reassure the visitors that the winged sumac in question was harmless.

There are some conspicuous differences, and other, conspicuous similarities, between poison sumac (Toxicodendron vernix) and the other sumacs of the Island. The others are not poisonous, and are staghorn sumac (Rhus typhina); smooth sumac (R. glabra); and winged sumac (R.copallinum).

Poison sumac is a small tree found only in wet areas. “Sumac” is a misnomer, like many common plant names. It is related to poison ivy and poison oak, and not to the Rhus sumacs. It grows exclusively in wet and clay soils, usually in swamps and peat bogs, while, conversely, the Rhus sumacs occur in sandy or dry habitats.

The berries of poison sumac are white and hang loosely in bunches, while the Rhus bear upright, tight cones of fruit. Poison sumac and Rhus sumac share leaf formations that are pinnate: individual leaves attached along a stem (rachis) to form a compound leaf. They support wildlife, share colony-forming tendencies, and they share gorgeous, flaming autumn colors.

Massachusetts Prohibited Plant List

A note about the Massachusetts Prohibited Plant List seems like a good idea, since its recent mention in the news and this column. Sounding like something akin to “banned in Boston,” or provoking a “not going to tell me what I can plant” reaction, the MPPL ( is in fact an attempt to safeguard the natural, ecological, and agricultural resources of the commonwealth by controlling the sale and importation of plant species with known noxious or invasive aspects.

The website of the US. Department of Agriculture National Invasive Species Information Center ( links to Regional Prohibited Plant Lists, as well as an interactive map for individual state lists.

In the garden

As with fall-planted bulbs, suppliers of seed garlic ship from September to November, depending upon where you garden (northernmost areas first). I earlier wrote that I planned to prep my vegetable garden for planting shallots and garlic; the time has now come. We removed the previous crop, collards; Portuguese kale replaces it in another section of the garden.

Prepping consists of weeding and soil cultivation; fertilizing with low-number, organic soil food; and covering the ground with straw litter. The actual planting, in my opinion, is best put off for later. This is to retard the sprouting of the garlic tops so freezing and thawing over the winter do not damage them. (Not everyone does it like this; as with many aspects of gardening, people arrive at different ways of doing things.)

I plant in rows about two feet apart, with the individual cloves two inches deep and six inches apart. My preference is for hardneck garlic; the cloves are generally larger and easier to peel — lazy me. This form does better in colder areas, since it requires exposure to cold temperatures. Note, however, that hardneck garlics have a somewhat shorter storage life than softneck ones.

Other areas of the vegetable garden are now open as warm-weather crops, such as zucchini and eggplant, are cleared away to make room for broccoli, kales, rapini, and other brassicas. Regular spray application of Bacillus thuringiensis (Bt) continues necessary, while white cabbage butterflies, with their preference for members of the brassicas, are still flying.

It seemed the zucchini plants have lasted very well this year. Many other years, collapse, usually from borers, occurred prematurely. It was a funny year in other respects. I had nothing that was ready in time to enter in the fair. We waited and waited for peppers, cucumbers, and tomatoes. Practically everything except beets and lettuce took its time to arrive at ripeness and picking.

‘Garden Wisdom: 365 Days’

Cheryl Wilfong’s “Garden Wisdom: 365 Days,” (Heart Path Press) has reinforced my opinion that in gardens and gardening are found many solutions to the unevenness of life: It does not matter too much whether one is gardening with hardened pragmatism or dreamy spiritualism. The work tells us what to do, and then the rest is up to us, accompanied, very often, by contemplation.

I have found myself reading meaningful words from “Garden Wisdom” almost daily. This past season has seen more hustle and bustle on the Vineyard, hassles of noise, traffic, heat, or rude people; and there has been a great deal of political discontent in the air as well. It is well to have something to tend and nurture, a pot of petunias, or a vegetable garden that feeds a family. And, it is well to have something to read that puts it into perspective.

“Garden Wisdom” is an almanac or chapbook of short pieces, one per day in the gardening calendar, that may be just the right prescription for what is happening in one’s garden, with oneself, and within oneself. Wilfong is the author of more than a dozen books and teaches Insight Meditation in Vermont.