Autumn Is For Planting

Mon, 09/28/2015 - 4:00pm
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By far my favorite time of year is autumn. The ocean seems a clearer, deeper shade of prussian blue, becoming a perfect canvas for the glint play of seasonal light. The heft of summer air is dissipating as the bees flit expeditiously, gathering nectar for the winter. The landscape is softened by the inflorescence of grasses and punctuated by stoic seed heads — milder days taking on the atmosphere of a Maxfield Parrish.

In the garden, autumn heralds the planting of cool weather edibles and the swan song of harvest for summer verdure. With the air temperature cooling and the soil still warm, perennials can develop strong root systems before winter without the need for excessive fertilization and with less risk of insect damage. That being said, what to plant?
I find myself obsessed with perennial herbs and edibles. Beautiful and salutary, they easily merit a spot (or 13) in the mixed border.

1. An absolute favorite would be Russian comfrey (Symphytum x uplandicum). Deer resistant comfrey blooms raspberry buds maturing into lavender blue bells loved by the bees, and will spread into a monster clump in fertile soil. In my sandy garden it thrives and behaves. Given the moniker 'knitbone', comfrey has a high allantoin content and can be ground into a poultice and slathered on the skin to accelerate the healing of bones. It works. Comfrey has lots of nitrogen, phosphorus and potassium coursing through its veins and makes a wonderful compost tea and mulch. When planting tomatoes, I line the dug holes with comfrey leaves for good result.

2. All hail sea kale (Crambe maritima). This truly perennial kale with thick glaucous leaves boasts dainty white blossoms scented of honey in May, that are delicious tossed in salads or cocktails. Once grown by Thomas Jefferson, sea kale is best when blanched by mounding sand on the crown. Young shoots are similar to asparagus.

3. Native mountain mint (Pycnanthemum muticum) won't take over your universe but you might wish it would. Silvery bracts collar pale pink flower clusters from summer through fall, inviting in a bevy of butterflies, bees and beneficials to keep the pollination game high in the garden. Deer resistant and loaded with the compound pulegone, mountain mint will keep the mosquitoes at bay as well.

4. Plant 'Arp' hardy rosemary (Rosmarinus officinalis) for remembrance. Hardy to zone 6 (-10 degrees), this regal evergreen has weathered five years in my Portsmouth, RI garden. On more than one occasion last winter I found myself shoveling snowdrifts, unearthing this redolent shrub to spice up a dish of oven roasted potatoes. It can grow to a sizable three feet tall by three feet wide, and then some. The soft blue flowers are anticipated in summer, and deer won't nibble.

5. My fascination with the historical virtue of certain plants leads me to suggest rue (Ruta graveolens) also known as Herb of Grace. Honored by Pliny The Elder and used in very small doses in Mediterranean cuisine (it is possibly toxic in large amounts), I would grow rue for the simple fact that I've witnessed Eastern Black Swallowtails use it as host plant. That is to say the butterflies will lay eggs on rue so that the caterpillars that emerge may feed on its foliage...which, by the way, is delicate, blue and lacy, but the deer will leave it alone. The cheery yellow flowers resemble ecstatic little starbursts.

Scott Anderson, herb grower at The Farmer's Daughter in Wakefield, RI, suggested a few of his favorite perennial edibles as well:

Garden sorrel (Rumex acetosa) lends a fresh, lemony bite to spring salads and soups and can replace the basil in an early batch of pesto.

Salad burnet (Sanguisorba minor) is a green with a light cucumber flavor that holds some valor historically as well. Recommended by Sir Francis Bacon, the leaves make delicious vinegars and butter, and the flowers are little tawny pink poppets held high above the leaves.

Lovage (Levisticum officinale) was touted as an aphrodisiac by Charlemagne, but Scott says it "changes the whole dimension of my black bean soup." This stately fresh green tastes of strong celery and works in a Bloody Mary just fine. Tall and lush, lovage bears yellow umbels in summer.

Last but not least, Scott recommends planting cutting celery. Not quite as potent as the mighty lovage, cutting celery has a "mellower flavor and lower will to flower and go to seed, a plant better suited for small spaces."

Autumn sets the stage for numerous varieties of ornamental grass. They can be effective in foundation plantings to soften corners and create a modern architectural style when planted en masse. Grasses are an integral element to open habitat gardens, mingling naturally with native flowers. They exhibit graceful movement in a static landscape and become a garden's bones when blanketed with snow in winter. Native species are the most disease resistant, tolerant of drought for xeric areas and require no excess fertilization. Mike Yarworth and Jane Case from Blue Moon Farm in Wakefield, RI specialize in growing native perennials and suggested the following ornamental grasses as an alternative to planting invasive exotic species:

Big bluestem (Andropogon gerardi) grows four to eight feet tall with blue/green foliage. It's a nesting source for birds and a larval host for butterflies. 'Red October' and 'Indian Warrior' are cultivars recommended for their rapid seasonal growth and attractive burgundy foliage.

Little bluestem (Schizachyrium scoparium) grows around three feet tall. A hot, dry garden brings out the technicolor hues on this grass. 'Standing Ovation' has steely aqua blades that take on shades of peachy copper and plum and resist flopping.

Switchgrass (Panicum virgatum) grows three to four feet tall and has high ecological/wildlife value. Best cultivars are 'Dallas Blues' reaching a height of six feet with blue/green foliage and pink, billowy seed heads, and 'Shenandoah' whose leaves turn red beginning in June.

Muhly grass (Muhlenbergia capillaris) grows three to four feet tall. Planted in groups, the pink clouds of inflorescence show incredible visual color when backlit. This grass needs a spot with impeccable drainage in winter.

Indiangrass (Sorghastrum nutans) also grows three to four feet tall. It is an anchor species for meadows and a good source of nectar for bees.

Trustom Pond in Matunuck showcases all of these grasses (with the exception of Muhly grass) in their natural habitat. This time of year it's absolutely stunning to view and supports a spectacular assemblage of native wildlife and birds!

Think about giving these wonderful green spirits a place to flourish before the season ends or perhaps dream of planting them in spring. Nourish nature and grow food and flora for the good of all!

Heather Russo has grown perennial plants for The Farmer's Daughter in Wakefield and currently for Mello's Farm and Flower Center in Portsmouth for the past 10 years. With a background in estate gardening, she has won awards for her garden design and container plantings at The Newport Flower Show and is available for garden consultation, presentations and workshops.