What to do this week As summer winds down, we let the garden wind down, too, as plants begin to prepare for winter dormancy. Stop fertilizing perennials and roses. But if you neaten up the perennial garden, it can still look spectacular in September. I cut back the yellowing and tattered foliage of plants that have bloomed already such as daylilies and iris to make room for those that have yet to bloom, including mums and asters. Deadhead annuals and harvest vegetables religiously to keep them producing. Fall is an important season for butterflies and other pollinators, so I grow a lot of fall-flowering perennials such as Canadian burnet, autumn monkshood, autumn anemone, Joe-Pye weed, late phlox, roses, New England asters, and goldenrod. I don’t plant goldenrod; it just pops up. It feeds pollinators and does not cause hay fever, which is instead triggered by the less showy ragweed that blooms at the same time. Only after goldenrod finishes blooming do I cut and bag the seedheads so it doesn’t spread too much. I don’t cut down milkweed, because if monarch butterflies laid eggs on it, it could be hosting their caterpillars.
Q. My question is about what to plant instead of privet for privacy hedges on Cape Cod. I hate the incessant sound of hedge clippers. I don’t like their smell, either! I prefer native plants that are not invasive.
A. Planting a privacy hedge that has to be sheared constantly is like growing a vertical lawn someone has to mow, creating lots of air and noise pollution, plus expense. If you are looking to prune only once a year or less, R. Wayne Mezitt of Weston Nurseries in Hopkinton, Hingham, and Chelmsford suggests columnar forms of rose of Sharon (hibiscus syriacus), a tough, deciduous summer bloomer with hollyhock-style flowers that likes beachy locations and grows 8 to 12 feet high and spreads 6 to 10 feet wide. I adore old-fashioned fragrant French lilac hedges (syringa vulgaris), but they bloom in May before most people move into their beach houses. Rick Peckham of Peckham’s Greenhouse in Little Compton. R.I., (peckhamsgreenhouse.com) suggests evergreen hollies, including the blue holly hybrid Castle Wall (ilex x meserveae ‘Heckenstar’) or Dragon Lady (ilex x aquipernyi ‘Meschick’), as well as the wild form of native inkberry (ilex glabra), which can grow 5 to 8 feet high and wide (but not the named dwarf varieties). Peckham also suggests ninebark (physocarpus opulifolius) which has June flowers and colored leaves. ‘Diabolo’ is a variety with chocolate mahogany foliage that can grow 4 to 8 feet high and wide. Perhaps the best native viburnums for hedging are the arrowwood (viburnum dentatum), which can grow 6 to 10 feet tall and wide, and the highbush cranberry (Viburnum opulus var. americanum), which can grow 8 to 12 feet tall and wide.
Remember, hedges for summer houses do not need to be evergreen. Western arborvitae (thuja occidentalis) is a popular evergreen privacy hedge solution farther north, but its foliage would burn under the seaside’s bright sun, Peckham warned. Like politics, all gardening is local. So ask your local nursery what privacy hedge plants thrive in your area, especially if you have special conditions.
Q. I wonder why you diverge from the usual recommendation for sugar water for hummingbirds: ¼ cup white sugar dissolved into 1 cup hot or boiling water. As their migration approaches, I increase the sugar a bit, but my hummers seem happy with their “juice’’ otherwise. By the way, I’ve kept my birdbaths filled also. Never had more bathers than this year, even on rainy days. No sign of sick birds.
A. Thanks to all the sharp-eyed readers who pointed out my mistake. I meant to write a 4-to-1 ratio of water to sugar. Our ruby-throated hummingbirds (plus two fledglings) are soon heading south but we keep our sugar-water feeders refreshed through September for more northerly migrant hummers who drop by on their way south. No sign of sick birds here either. This summer’s mysterious bird blindness disease seems confined to more southerly regions that, unlike New England, saw a cicada emergence.
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