Summer Gardening and Flowering Plants

It is July, and though the solstice has passed, true summer is bookended by Independence Day and Labor Day, two months’ reward for seemingly six months of winter. Time is set aside for travel, vacation, summer camp, rest and relaxation. However, it is still a good time to garden, despite the old notion that it is too late in the season to plant. Indeed, this used to be true: when plants used to be field-grown for transplanting into a new garden, digging them up in the summer was risky business. Today’s plants, from trees, shrubs and vines to perennials, are grown in containers to make their transition into the ground practically stress-free. While it is true that summer additions to the garden must be watered, it’s equally true for those plants that were put in this past spring. (Please, don’t rely on lawn irrigation systems to do the job for you, unless you have a dedicated drip zone. Lawn irrigation does not water deeper-rooted plants sufficiently.)

The fireworks that light the skies on the Fourth are echoed in the flowers of summer, as July and August are the months of Coneflower (Echinacea) whose large bright daisies burst into dazzling and clean displays of traditional dusky pink (such as the standby cultivar ‘Ruby Star’,) but newer hybrids now offer shaggy mop-headed types such as the orange ‘Marmalade’ and ‘Hot Papaya’. ‘Evan Saul’ (Sundown™) evokes a desert sunset, with bright orange “petals” highlighted with rosy-purple. ‘Green Jewel’ offers cool light green “petals” – a unique color – surrounding a central green cone. Coneflowers are butterfly magnets, and their brown seed heads are prized by finches in late summer and beyond. They all do well in sun to part shade, and are drought-tolerant once established.

We are well-stocked with interesting and well-grown trees and shrubs. Our specimen Stewartia tree planted beside the barn has been flowering since June 20, and is just halfway done blooming, an inspiration for the smaller ones we have ready for planting. Summer-blooming azaleas are hardy, colorful and fragrant, and are superb for planting near a deck, patio or pool, where their sweet scent may be enjoyed in the day or evening. Several varieties are offered, and are in flower now. Buddleias (Butterfly Bushes) are budded and will be opening soon, as will the many types of Clethra (Summersweet) that we carry.

Ornamental grasses are now coming into their own, and will only continue to get bigger and better through the season. Plant them now to enjoy through the fall, as most types need the warm soils of summer to become established before winter.

Astilbe at The Mixed Border

And for the shadier gardens, our Hostas are spectacular, as always. We have on hand over a hundred varieties, from tiny-leaved miniatures such as ‘Baby Booties’ to ‘Empress Wu’, the largest Hosta to date, and with a wide choice in leaf colors and patterns of variegation. Astilbes are coming into flower, and we have a good selection of perennials, wildflowers and ferns for shade.

We welcome your visit.

Nursery Hours, July to September:

Monday: 9:00 am to 5:00 pm
 Thursday through Saturday: 9:00 am to 5:00 pm

Sunday: 10:00 am to 3:00 pm

We are closed on Tuesdays and Wednesdays, except by prior arrangement.

Please note that in the event of dangerous weather (such as thunderstorms or extreme heat) we may close earlier than scheduled, for everyone’s sake. Please call ahead (603-882-5538) if bad weather is forecast on the day of your visit.

Selecting, Planting and Caring for Peonies

We offer both herbaceous and woody (or tree) forms of peonies. The most familiar garden peonies are the herbaceous types, with showy and colorful flowers in May to June, depending upon the variety. Each blooms for a week or more. They are cut down to the ground each fall and rise again in the spring.

Tree peonies maintain woody stems which bear large leaves that drop in the fall, and their flowers are enormous: often up to ten inches across! These blossoms open and fade all too quickly, especially when grown in afternoon sun (although they need at least ½ day of sun to bloom well.) Thanks to the late breeder Mr. Itoh, there are also many “Itoh” or “intersectional” hybrids now available, which have both an herbaceous and a woody parent. These are some of the finest peonies available, with herbaceous foliage resembling that of their woody parent. Enhanced vigor and a longer bloom period, including varieties with yellow flowers, distinguish them from other peonies.

Peonies in The Mixed Border's garden

Flowers are typically classified as Single, which have showy petals surrounding functional carpels and golden-yellow stamens (reproductive parts); Japanese, with large outer petals and clusters of enlarged anthers sometimes edged in yellow; Semi-double, in which inner petals have formed within the ring of outer petals, and still contain functional reproductive parts; and Doubles, whose stamens and carpels have been transformed into a dense display of petaloids surrounded by the outer petals. With the large number of varieties in cultivation, there is often some overlap of these various forms, but I have tried to keep it simple. The Singles and the Japanese forms will tend to remain upright in flower, while the heavier Doubles may flop under their own weight. Support of these types may be recommended to keep the flowers off the ground; a subtle corset of bamboo canes and garden twine is usually enough. Peonies usually require a couple years to get established after planting to display their full floral qualities. Flower color can be affected by strong sun (fading of deeper colors) or cool weather (white varieties can develop pink tones.)

Most (but not all) peonies are fragrant, with the pink or white doubles usually your best bet for a scent that is typically rose-like. Red peonies, though pretty in the garden, don’t always make the best cut flowers, as their aroma isn’t always desirable. Some tree peonies are mildly lemon-scented.

Peony 'Krinkled White'

How to plant peonies:

As long as the planting site is well-chosen and well-prepared, Peonies will live for many decades with little care. Hybrid peonies perform best with at least a half day of full sun, and excepting tree peonies, more is better. If given the choice, some afternoon shade can help to reduce blooms fading in color or “going by” too quickly.

Well-drained soil is important, as areas which remain wet for periods of time may cause their thick and fleshy roots to rot. Because they are so long-lived, they deserve and need a planting hole that is deep and wide, and contains a good amount of organic matter such as compost. Dig a hole at least the size of a 5-gallon bucket and remove the soil, discarding any sand or gravel and reserving the topsoil or loam. To that, add an equal amount of compost (avoid all but extremely well-aged manure) and a handful of lime and organic fertilizer. Fill the hole with this mixture, such that the plant’s soil surface will be at (or slightly above) the soil level outside the hole. Take care not to place soil on top of the roots, either now or at some future time, as their flower buds will not form if planted too deeply. Mulch very lightly with good compost or a thin layer of shredded bark, and water well.

Do not allow the plant to dry out until well-established (usually within one year.) Peonies are drought-tolerant, but may go dormant early and flower poorly (if at all) the next year if not kept reasonably moist throughout the growing season. Fertilize each spring or fall with organic fertilizer.

Peony 'Sorbet'

Peony problems:

My peony doesn’t flower. Why? Peonies planted too deeply may not flower, nor will those grown in poor soil or shade. Keep the foliage vigorous and healthy.

Some of the leaves and flower stems have wilted and turned brown. Botrytis is a blight disease of peonies that happens most often when the foliage remains moist, sometimes due to rainy weather, or because of overhead irrigation (typically from lawn sprinklers.) Clip off the diseased parts, cleaning your clippers with rubbing alcohol between cuts. Throw the diseased stems in the trash. If needed, an appropriate fungicide may be applied as a preventative (but they rarely are curative.)

Guide to Successful Planting and Care

Before you plant...
Can't plant your purchases right away? Relax! Plants in containers will remain in good health for a long time. Just make sure that they are watered regularly so that they don't dry out before you are ready to plant them. A slightly shady spot will be beneficial. Balled-and-burlapped (B&B) plants may also be treated the same, except that a mulch around the roots will slow down water loss and keep the roots cool until planting. If you have any questions after reading this planting guide, please give us a call at 603-882-5538.

Soil preparation...
Adding at least a couple of inches of organic matter such as Coast of Maine^tm compost over the surface of the bed, along with perhaps a dusting of powdered limestone and a sprinkling of a good organic fertilizer, such as Pro Gro^tm. Then turn them all into the soil to a depth of at least 6 inches. Rake smooth, and the planting will be easy. Unless adding a plant to an existing bed, don't cheat by just amending the soil removed from the planting hole, for the roots need to be encouraged to be developed beyond it. This is especially true when planting trees and shrubs. Many studies have shown that amending the soil only within the planting hole actually inhibits root development beyond it. The roots need to grow into the surrounding soil, and the sooner that happens, the faster and better the plant will become established.

Note: plants that are said to require "good drainage" usually need some sand added to the soil, rather than organic matter.


Drawing by Tom Strangfeld. Used with permission.

Planting...
Dig a hole at least twice as wide as the rootball; wider is better, especially for trees and shrubs, but no deeper than the height of the root ball. (Exceptions would be roses, clematis, and peonies: these will generally do best in a hole dug about the same size as a 5 gallon bucket, with richly amended soil). If the soil has been prepared as earlier explained, no additives are needed.

After digging the hole, remove a potted plant from its pot and examine the roots: any that are encircling the soil should be gently pulled apart with fingers. More substantial roots that encircle the pot can be cut or teased away with an old knife, trowel, or spade. Set the plant in place, and after making sure that it is facing the right direction and is plumb, fill the hole with soil level with the top of the root ball but not covering it. Press the soil firmly with your hands, and add more if needed to be level with the top of the root ball. (See illustration.) Water well.

Balled and burlapped plants are installed the same way, except that any twine should be cut off after the plant is set in the hole, and the burlap loosened and gently cut away with a utility knife. Wire baskets should not be removed, as they help keep the root ball intact. (See illustration.)

Then, mulch the soil with a 2-inch layer of shredded bark or other material of your choice. Please do not mound the mulch up around the stems.

Mulches...
Organic mulches of many sorts are recommended: shredded bark; buckwheat or cocoa hulls; compost; shredded leaves; and even pine needles (the answer is no, they don't make the soil more acidic, but you can add a little extra lime if you aren't sure). All mulches add valuable organic matter to the soil as they decompose, so top-dress as needed. Avoid mulch volcanoes around trees! Pea stone makes good mulch for plants that prefer dry, gravelly soil, such as those found in rock gardens.


Drawing by UMass Extension. Used with permission.

Watering...
Lawn irrigation systems are not suitable for watering trees, shrubs and perennials. Consider installing a reliable, waterconserving drip irrigation system. Newly installed plants should not be allowed to completely dry out. Watering depends upon many factors: season, water needs of plant, exposure to sun or wind, weather, etc. Check the soil regularly for dryness. Dry soil falls apart when handling it; moist soil feels cool and retains its shape somewhat when squeezed. Water deeply rather than shallowly. Do not depend upon natural rainfall when establishing plants!

Aftercare...
Fertilizer, whether synthetic or organic, may be applied in the spring or fall. Organic forms are best, as they feed the soil rather than the plant, and release their nutrients slowly. We recommend Pro Gro^tm.You may choose a specialty fertilizer, or an all-purpose 5-10-5 or close equivalent. Adding a thin layer of compost each fall contributes valuable organic matter as well as a modicum of nutrients, which feed the soil. You'll see a difference the next year in your garden.

Winter Protection...
Perennials benefit from a light mulch applied in late fall, after the soil has frozen. Salt marsh hay is the best, because it contains no weed seeds, and lasts for a few years if dried and properly stored the next spring. Check The Mixed Border Nursery and Gardens for availability. Otherwise, use evergreen boughs, such as recycled Christmas trees or straw. Uncover gradually in late March or very early April, after the snow has melted.

Trees and shrubs usually need no winter protection, except for evergreens, which often benefit from screening out the winter sun and wind for a year or two after planting. A roll of burlap works well. Various wraps applied to the trunks of trees are usually not recommended.

Please remember that gardening involves nature, and weather cycles can affect the winter survivability of plants in the landscape, despite our best efforts.

Pruning...
Pruning is a subject unto itself. Suffice to say that most people do not prune plants properly; plants are often sheared into shapes ranging from golf balls and hockey pucks to chicken nuggets. A better method is to selectively thin out branches that have become too long, or too dense. Restraint, and a good book on pruning is helpful, or call us at The Mixed Border Nursery and Gardens to have us do the pruning the right way, at the right time.

Problems?...
Although we strive to sell only pest-resistant plants, occasionally insects or disease affect plants. Please be sure to identify the problem before treatment to avoid possible environmental harm. Call us, or contact your county Cooperative Extension Service office. In Hillsborough County, NH, the contact number is 1-877-398-4769 or UNH Cooperative Extension Service.

Our Guarantee...
We guarantee that our plants are true to name and in healthy condition when they leave the nursery, and will not knowingly sell any otherwise. If you have a problem with one of our plants, please let us know about it as soon as possible. Most experienced gardeners realize that losing plants occasionally is part of gardening. Sometimes plants perish due to unusual weather, improper planting or aftercare, or placement in the wrong location. Rarely will plants fail due to insects and disease. The Mixed Border Nursery and Gardens will not be liable for any such losses. If a plant fails to survive within 30 days of purchase, we will provide, at our discretion, full replacement or store credit based on the purchase price. Responsibility for losses beyond 30 days will be shared with the gardener, and we will offer a 50% store credit based on the purchase price of the plant. We cannot extend our policy beyond 90 days from the date of purchase or beyond the year of purchase, whichever is sooner. Plants purchased on sale are excluded from any warranty. All returns must be accompanied by the original sales receipt and plant in question. (Effective 6/1/06) Plants installed by The Mixed Border will be warranted for a period of one year following the date of planting. Certain conditions apply.

When to Plant?

"But it's too late to plant!" said my sister the other day when she asked for recommendations about what to plant around her house. "Don't I need to wait until fall?" These questions are frequently asked, indicating the widespread but incorrect belief that all plants must be in the ground by Memorial Day, or they won't survive.

In fact, plants can be installed almost anytime that the soil isn't frozen. Better plant harvesting techniques and the culture of plants in containers have removed the barriers of planting in summer. When I told her this, she then asked another common question: "But won't I have to water it more often in the summer?" The answer is yes, that is true, but you also have to water plants installed earlier in the year throughout the summer as well, so there is little difference.

Such myths are unfortunate, because they cause people to think that the only time they can create or improve their gardens is confined to a very narrow window of time. This results in a rush to get things done in the spring, instead of at a more relaxed pace throughout the 6 or 7 months that it is safe to plant. Such belief also creates a frequent complaint of gardeners: that they don't have enough color in their gardens after June. Gardeners usually choose plants that are in flower when they purchase them. If they are making their plant purchases in the spring, then it is no wonder that their gardens are only green in the summer or fall. Now is the time to add more color to the garden, besides the use of annuals. There are many plants that will flower in early to midsummer, and from late summer to autumn: from deciduous trees, shrubs and vines, to hardy perennials. Late-blooming spireas are just now coming into flower, as are potentillas and even summer-flowering azaleas such as the variety 'Pink and Sweet' and others. Late lilacs continue to bloom, well after the familiar French hybrids have faded into memory: 'Donald Wyman' and 'James MacFarlane' included, as well as the Japanese tree lilac (Syringa amurensis). Soon to follow is the rare but hardy stewartia (Stewartia pseudocamellia), whose botanical name reveals that its flower resembles a white camellia, opening throughout the summer.

In mid-July and after, the butterfly bushes (Buddleia davidii hybrids) are in bloom. An earlier column highlighted these colorful and fragrant plants that will remain in blossom until fall. Summersweet, a hardy native shrub, also blooms in July, bearing fragrant flowers that are creamy white, and sometimes slightly pinkish. The compact form of this plant (Clethra alnifolia 'Compacta') is one of my favorites for summer blooms.

Also consider that many plants offer wonderful foliage for about 6 months of the year, and that the leaves can be quite colorful. There are many forms of Japanese barberry (Berberis thunbergii) that come to mind, from the relatively common compact 'Crimson Pygmy' to 'Rose Glow', which has wonderfully variegated leaves which are splashed with pink, cream and purple on the new branches. 'Gold Ring' has a thin golden margin around each leaf on the new growth as well. 'Golden Nugget' is a new, quite compact form with bright yellow leaves throughout the summer on a tight mound-shaped plant. Other variegated and colorfully-leaved plants also come to mind, such as the variegated shrub dogwood (Cornus alba 'Argenteo-marginata'). Such plants work well with perennials in the mixed border garden, whether in a foundation planting or further from the house.

As for perennials, there are many that will bloom for a long time, once the days turn warm. Salvias such as the variety 'Blue Hill' honored as plant of the year by the Perennial Plant Association, Knautia, Scabiosa 'Pink Mist' and 'Butterfly Blue' all will flower throughout the summer, with periodic deadheading. And remember Hostas for their foliage effects as well as their later flowers.

Daylilies are now coming into bloom, and there are many varieties to choose from, from early- to late-season bloomers. Many of the newer hybrids also have an encore performance a few weeks after the initial show of flowers. Tall garden phlox (Phlox paniculata hybrids) will soon be in bloom as well. Choose the forms that are powdery-mildew resistant, such as the pink 'Eva Cullem' or the white 'David'. Russian sage (Perovskia atriplicifolia) is a welcome addition to the August garden, with its stalks of bluish flowers and grey foliage. And soon, plants for the summer meadow or border will be on display. Tall coreopsis of different types, rudbeckias, coneflowers, and many others can be planned and planted now for cheerful late-summer flowers, and consider some grasses to complement them in the garden.

As you can see, the flowering season needn't stop when the first day of summer arrives, nor should the gardening season. Take advantage of these warm, pleasant days of sunshine that we have yearned for since late last summer. Decide what your garden needs for summer beauty, and do something daring. Plant it.


The previous article originally appeared in the Hollis Times, Hollis, NH.