Garden Notes

Red camellias (like these currently blooming at Polly Hill Arboretum) are so gorgeous they look almost unreal. They can enliven any Island garden in spring. Photos by Susan Safford

Watchful waiting

By Abigail Higgins - May 11, 2006

Budbreak is normally a time of pleasurable anticipation and excitement in gardens and the great outdoors, and it is true especially on the Vineyard where we must wait so long for spring to arrive. This year, however, it is freighted with a sense of anxiety and downright foreboding as we await the countdown to emergence of caterpillar activity. We know they are there, but the obvious activity and damage are yet to be gauged. The eastern tent caterpillar nests, especially in crotches of wild cherry trees, are in evidence and one week ago (May 5) were about the size of an apple. In April I saw clusters of minute, eighth-inch long caterpillars in oak woods that I took to be forest tent caterpillars from their appearance.

Homeowners in locations known to be at risk will have already taken steps to have spraying performed at the critical windows-of-opportunity for the multiple species that are in outbreak mode here. Those elsewhere are nervously watchful to see where the outbreaks will spread. One way to lessen one's anxiety is through information, and for those enquiring minds so inclined, interesting information on the interrelated cycles of oak forest, acorn masting, deer and white footed mice populations, gypsy moth outbreaks, and much more, is available online at

Each shoot on this climbing rose cane will sprout flower buds when it is bent down and horizontally trained.

Also on the educational front, this timely program notice from the Polly Hill web site: "On Friday, May 19, from 1 to 3 pm the Polly Hill Arboretum will host Deborah Swanson and Bob Childs from the UMass Extension Service.

"Horticulturalist Deborah Swanson will focus on reducing pesticide usage through choosing resistant plant material in her talk, 'Great Plants of Sustainable Landscapes.' Entomologist Bob Childs will follow up with Integrated Pest Management in landscape plantings. Bob will lead a walk through the Arboretum for demonstrations of IPM tools and techniques, stressing proper insect identification and least toxic (bio-rational) management. Bob will also give us an update on caterpillar pests on the Island. Participants may earn two pesticide re-certification credit contact hours for categories, 29, 36 as well as ISA credit, forms will be provided. Dress for walking; workshops are held rain or shine. Meet at the PHA Visitor Center. Please call to register. $20/$15 for PHA members. 508-693-9426."

Beware garlic mustard
While on the dual subject of nervous watchfulness and timely information from Polly Hill, I received a bulletin on garlic mustard from PHA's Karin Stanley. Apparently, garlic mustard (Alliaria petiolata) has turned up in adjacent property to the Arboretum grounds; I know this invasive weed from one site in Edgartown near the Harbor View Hotel. From the article Karin forwarded to me, I became additionally informed about this monster, and monster it truly is, for a fascinating reason. Garlic mustard apparently has no need of the mycorrhizal fungi that normally inhabit soil and symbiotically create optimum growing conditions for most of our native trees and flora. The mycorrhizal fungi help make soil nutrients available to plants, getting carbon in return. But garlic mustard, also a prolific seed-setter, has evolved anti-fungal properties that kill off these soil fungi that it does not need, leaving the native plants deficient and easily overwhelmed by the multitudes of garlic mustard seedlings. Soon, in an infested area, there is nothing but a carpet of garlic mustard.

Camellia ready for her close-up.

Stop for a moment to consider the ecological ramifications - throughout the habitat food chain - of a plant that stunts or kills everything around it! Where will the small animals and insect life, which need the native plants for food, forage when the woods are carpeted with only garlic mustard? Where will the birds and amphibians that live off those life forms find their meals? What will the predators and raptors in their turn eat? Dendrologists (people who study trees) say that when garlic mustard shows up in a forest, the tree species themselves that become the canopy are most at risk. How would our woodlands look if, already weakened by caterpillars in outbreak mode, the native trees and understory were additionally suppressed and poisoned by an invasion of garlic mustard?

Garlic mustard is often recognized by the fact that when one sees it, it is in drifts or carpets. It is low growing, biennial, with toothed, triangular-to-heart shaped leaves that somewhat resemble money-plant (lunaria spp.) The second year the plant elongates and sends up a flower stalk of the four petaled (typical crucifer) white blossoms. The leaves have a garlic-like smell when crushed. The only good news about this terminator plant is that when young its root system is weak and it pulls or is cultivated out easily. This is an appeal to Island gardeners to learn to recognize garlic mustard. Please pull it out wherever you see it. Images of it appear on

It's in the name
Island agriculture is alive and growing and needs our support. A group calling itself the Island Grown Initiative (IGI) has been evolving to showcase and encourage the production of Island-grown food. IGI has planned publicity, events, an informational map to Island farms and locations to purchase Island products, and an "Island Grown" logo to identify them. Please watch for further information over the coming weeks and plan to become a part of the local agricultural economy.

Cognitive dissonance
An irony of writing Garden Notes that is not lost on me is that I am often to be found on the weekend indoors writing this column instead of outside, "in my element." I have mentioned pruning several times in recent columns, but guess whose own roses have mostly gone un-pruned? I am just getting to the jungle of 'New Dawn' climbers on my fence. There may be others who are for any number of reasons dilatory like me in this: cheer up and get on with it! The idea with roses is first to cut away any canes with discolored or winterkilled bark. The idea with climbers is to tie in or train the canes into as horizontal a posture as possible, because then all the little laterals will become bloomers. (When allowed to grow vertically, the cane will still have laterals, but only those at the tip end will really flower.) Those laterals are then deadheaded after bloom, and through pruning can remain productive over a number of years. When a cane becomes too old and gnarly, it can be cut out and a younger one selected to replace it.

Reminder: COMSOG plant sale starts Saturday and Sunday, May 13 and 14 and continues through Monday, May 29.