September and drier air at last! Nighttime brings good sleeping conditions, extravagant dewfall and the trills of the cricket chorus.
I had excellent feedback concerning a defoliated Cornus alternifolia in the previous column: thank you to the interested readers who contacted me. Disappointment at no "baby" Prometheus moths changed to interest at observing this new-to-me insect in my neighborhood.
It appears that the insects in question are larvae of the dogwood sawfly, Macremphytus tarsatus, which explains why they did not appear in my handbook of lepidopteran caterpillars. Although they very much resemble a lepidopteran caterpillar, the adult insect is a wasp-like member of the Hymenoptera. The larvae are most frequently found on C. racemosa and C. sericea, shrub dogwoods grown for their stems' winter color, and the pupae are a favorite food of woodpeckers.
Another interesting fact about the dogwood sawfly is that they may create galleries in the wood of one's house to pupate in if there is no rotting wood on the ground nearby to over-winter in. Woodpeckers relish the pupating insects enough to attack the house or structure where sawfly larvae are pupating. Therefore the caution about this insect is that if structures are located close to afflicted dogwood plants they may be damaged both by gallery building and subsequent woodpecker activities. Luckily, our pagoda dogwoods are planted in woodland, surrounded by the potential lodging of caterpillar-damaged oaks.
While Christiantown's woods are rich in species and numbers of woodpeckers and also in dogwood, with many naturalized C. florida in the vicinity, I have never before seen a skeletonized dogwood or the dogwood sawfly. The skeletonizing of dogwoods, according to various sources of information on the Internet, generally poses no danger to the tree, occurring late in the season when the tree has made its growth and stored its energy for the year.
Eternal optimism: "Next Year Will Be Better"
Tomatoes are such a prized, eagerly awaited crop. Statistics show that if only a single home garden crop is to be grown it is likely to be tomatoes. To lose it is a very great disappointment. The 2009 growing season provoked many challenges, with gardeners who previously had always found a means of control suffering blights.
I did not think things were too bad in my own garden but heard many tales of woe over the course of the season. One of my peskiest problems has been, and has been for a number of years, incessant clouds of white fly, which I am certain do their share of spreading leaf problems; on the other hand, they seem to be eaten by ladybugs. Then, as of two days ago, wham - my late crop tomatoes are blighted, blackened on the vine!
When the vegetable garden appears to be winding down, it's time to begin planning for next year. Homegrown, Martha's Vineyard vegetable gardeners forum, starts up September 20, from 4 to 6 pm, at the Agricultural Hall.
Clean up, compost, cover crop: this is good practice for most gardens, irrespective of specific problems. Over time gardens, being food sources, accumulate food webs. Components of these will be pests, from the microbial to the vertebrate. Better fencing helps with the bigger pests. Having a planned rotation helps in controlling invisible ones - garden pathogens. There is no one best rotation system: different versions are set forth in garden books and Internet sites, but there are basic similarities. Since each garden has a unique set of crops, environment, and conditions, you the gardener make the decisions here.
Some plans feature a three-part rotation between root vegetables, beans and salads, and nightshade family members (tomatoes, peppers, eggplant). Others are four-part, including a fallow or cover crop part, or a brassica part. Photographing the garden layout each year may be a handy visual reminder after the intervening winter, of what grew where previously.
Though it is intended for larger growers, a protocol that many gardeners can use, "Disease Management in Organic Vegetables" by Sally Miller of Ohio State, outlines many steps and products: http://oardc.osu.edu/sallymiller/Extension/presentations/Organic Disease Management.pdf
Neatening and tidying, continued staking, and cutting back constitute much of the present garden work. Foliage of perennials that have gone by, like daylily, platycodon, alchemilla, or astilbe can certainly be cut back. Identify plants, such as phlox, helianthus, asters, and astilbes that would benefit by being lifted and divided. Once they are no longer in bloom or showing foliage it is harder to be sure you have the right one.
I grew achimenes ("ah-KIM-i-nees") this year from bulbs that I purchased from Brent & Becky's Bulbs. I ordered their entire color selection - red, violet, blue and white. I had not grown them for years, but they are just as colorful and pretty as I remember them. Achimenes, for those who are unfamiliar with them, are members of the gesneriad family, like gloxinias and sinningias. The moss-mat-lined basket containing them is visited every morning by hummingbirds.
Many shrubs and trees may be given light pruning for shaping. Deadhead caryopteris, potentilla, and 'Hidcote' hypericum.
Mulch now, rather than waiting for real autumn. In our new weather paradigm, the dead leaves take forever to fall, leaving one to rake, rake again, and spread mulch in cold temperatures and little daylight. Mulching early means not having to rake first. Before mulching beds a top-dressing of low number organic fertilizer may be laid as a soil food.
Many lawns have had a bit too much water/rain and fertilizer has leached away. Fall and spring aeration always seems like a good policy to me, but this year the fall treatment will be more beneficial than usual. Over-seed bare and worn spots.
Polly Hill Arboretum, Fall Plant Sale, Saturday, Sept. 12, 10 am-2 pm.