Garden Notes: Solstice days

Timing is important for planting and harvesting.


Summer is officially here, with the summer solstice this year on June 20. Fireflies announced the fact a little earlier: They have flashed for almost two weeks. Trees are in full foliage, which now hangs heavier on the branch. Although many are presently more homebound than they would wish, the opportunity to focus on the life of the garden and surroundings is also being appreciated more than usual.

Speaking of fireflies, it is saddening to learn that in many parts of the country, and world, fireflies are becoming increasingly scarce. Why is this so? According to, nobody knows for sure, but most researchers blame two main factors: development and light pollution. If you see many in your garden, congratulate yourself.

“How do I know …?”

Internet gardening know-how sites are peppered with questions that begin like that, or “Is it too soon to …?” For novice gardeners, many standard and usual practices seem arcane and hard to know.

A complex-seeming way is to track “Growing Degree Days (GDDs).” According to Wikipedia, GDDs are a practical tool in the study of accumulated heat, used by growers to predict when maturity of plants, animals, and insects will occur.

Some of this know-how is acquired, along with the rest of the gardener’s experience, from relatives and friends who have been doing it for longer. Some can be gleaned from state university extension services. Some come from seed catalogues and growing instructions on seed packets.

A way to know “what to do when” has an imposing sounding name: phenology. According to Wikipedia, it is the study of periodic plant and animal life cycle events, and how these are influenced by seasonal and interannual variations in climate, as well as habitat features such as elevation. In lay terms, phenology is the coincidences of things in the place where you grow.

A seat-of-the-pants version is the use of indicator plants: a well-known example is the advice to plant corn when oak leaves are the size of mouse or squirrel ears. I know I can cultivate when forsythia blooms; that settled, summer weather is here when heat-loving portulaca and crabgrass germinate.

Honeysuckle ‘Dropmore Scarlet’

Do you love having hummingbirds and butterflies visit your garden? Do you have a fence or gateway that could accommodate a vine? Is it semi-shaded? Then do consider the tough, floriferous, hummingbird attractor, Lonicera x brownii ‘Dropmore Scarlet.’

With almost continuously produced whorls of tubular scarlet flowers (and named for a British country house), a ‘Dropmore Scarlet’ honeysuckle strategically planted gives watchers a summerlong hummingbird theater for observation.

In my garden, the plant has been in place for years, and has been subjected to unintentional abuse by lumber piles, anchor chains, errant mowing, and other insults, yet it carries on, using a glacial erratic and holly ‘Edward J. Stevens’ for support. The blue-green foliage is problem-free. The one thing this honeysuckle does not do is provide fragrance; however, in return, it does not invade or self-sow, unlike some of its more promiscuous, profligate relatives. And of course it may be planted in full sun. However, a plant that thrives and flowers in deeper shade is on a shorter, more valuable list than the many, many sun lovers.

Gardens tend to become shadier as they mature, and this is not always a bad thing. However, it becomes problematic when the original planting and lawn do not flower or thrive as intended. Tree and shrub removal, or an altered planting scheme, become the alternatives. Keeping in mind a few dependable flowering plants for the inevitable shadier transition is a way to compromise.

Herbal harvest

At summer’s end, the West Tisbury police chief, George Manter, used to make a warning announcement, “Harvest time’s coming!” to home cultivators of marijuana. For herbs of another sort — those whose leaves are used for teas and cooking — summer’s beginning is the time to harvest, to avoid flowering.

It is accepted that flowering alters the qualities of leaves that are sought for herbal properties, such as flavoring and teas. For instance, basil’s flavor and leaf production deteriorate after flowering. The “true” French tarragon does not flower, but much that is sold as such does in fact produce tiny, ball-shaped flowers. For drying and flavoring vinegars, harvest before this.

The list of herb garden subjects used for teas and cooking is practically endless; at home we can easily grow and dry some of the most useful and commonly used ones: mint, sage, rosemary, lemon balm, red clover, and nettle.

It used to be prescribed quaintly to harvest herbs while “the dew was on them”; i.e., plants (and flowers) have the most value and vitality early in the day. Preferably, check for insects and things like spit-bug foam, but do not wash.

Lay out on screens, or trays with good airflow, to dry in the shade. When the leaves are crinkly-dry, store out of the light in Mason jars or canisters, or do as my daughter does — she further scissors them in the jar.

In the garden

Continue sowing warm-weather and succession crops, such as Malabar spinach, winter squash, and bush beans. Find or make a shaded spot — protection from summer’s heat — for salad greens.

Harvest potatoes a couple of weeks after flowers appear.

Digitalis (foxglove) had a banner year in spring 2020. Lay stalks of seedheads where you want to establish these shade- and deer-tolerant biennials, and watch for dustlike green seedlings.

Lepidopteran caterpillars will be showing up; plan a weekly Bacillus thuringiensis spray to control them on brassicas, tomatoes, squash vines, and others they target.

Cultivation at the two- or three-leaf-blade stage is the easiest way to control crabgrass in vegetable gardens. Lawns and driveway edges are more difficult, but I am astounded to see people still spraying their home premises with weed killers!

Polly Hill Arboretum

The PHA plant sales continue, online, at