September, Botanical Enlightenment

By Leslie Watkins

The autumnal equinox, September 23, marks the beginning of fall. The sun sinks lower in the sky, reminding us of shorter days to come. This is the light artists love. With some thoughtful planning gardeners can use light like this to great advantage.

One of the first considerations in making a garden is, how many hours of sunlight does it receive throughout the day? Is it a sunny spot with eight or more hours of direct sun, as required by many vegetables, or is it a shady spot, which hostas and ferns prefer? You may have to map the course of shadows, hour by hour, as they move across your property. Plants have light requirements or tolerances, which can be found on plant labels or online.

When assessing your garden light, avoid the middle of the day when the contrast is too strong and color is blasted by the overhead sun. The movement of light is best observed in early morning and late afternoon, when the sun is low and long shadows are cast. Color is at its richest then and even more so after a drenching rain. It is possible to control the quality and direction of light by planting trees or vines in places where their cast shadows are wanted. Dappled light is inviting, and a bright spot along a path can beckon your visitors onward.

More interesting than this is the play of light on plants. You can add an additional layer of interest to your garden at specific times of day by utilizing sunbeams. Plants between you and the sun become luminous beacons of transmitted light with bright flashes of color. Morning light on dew-covered asparagus turns it into a curtain of sparkling diamonds. As the sun dips in late afternoon, light passing through colored leaves and petals creates windows of stained glass.

Some plants have hairy leaves that capture droplets of water, refracting light into prismatic colors. The perennial Alchemilla mollis (lady’s mantle) is named for the alchemists who sought to turn base metals into gold. Drops of water rolling on its fuzzy leaves are reminiscent of liquid mercury. Other plants have pale petals and leaves that are highly reflective. They can light up the garden in moonlight, and many of these exude their strongest scent at the end of the day, making them ideal for folks who enjoy an evening stroll before turning in for the night.

September is the time to deadhead or mow weeds before they set seeds. You may not stop all your weeds, but you can slow them down a bit. Weeds to watch for include ragweed (not to be confused with goldenrod, a nice plant), purple loosestrife, Japanese knotweed, dock, bindweed and oriental bittersweet­—cut them at their roots.

The honeybees are getting ready for winter, and egg laying is greatly reduced as the hive contracts. Nectar flow is slowing, and the drones are disappearing. Be sure there is water available to them. See that they have enough honey stored to feed them through the winter, at least 60 pounds, or supplemental feeding may be necessary. The bees are still collecting pollen from asters, goldenrod and helianthus.

Illustration: “Alchemilla mollis,” Leslie Watkins © 2015 

September Chore List

• Harvest vegetable and flowers seeds.
• Repot houseplants to bring indoors.
• Divide and transplant perennials.
• Plant peonies and fall bulbs.
• Cure onions and garlic and store in basement.
• Remove or deadhead weeds before seed set.
• Close cut the lawn to discourage voles.
• Plant grass seed and cover lightly with compost.
• Freeze herbs rolled in ziplock bags.
• Dig up dahlias and tender bulbs.