Perennials
Fall-Blooming Perennials
By autumn, many of the spring- and summer-blooming perennials have faded, leaving the garden bleak and colorless. But some perennials, such as asters and goldenrod, will provide vivid color until the first killing frost or even later. If you decide to plant now, remember, the earlier the better, as the roots will benefit by giving them some time to get established before the ground freezes.
Here are some fall-blooming perennials
that will add color to your landscape
Asters (Aster spp.)
Hardy asters are a mainstay of fall gardens in northern New England. They are available in a variety of colors from white and pink to lavender, purple, and blue, and in heights from a foot to four feet tall. Asters prefer a sunny location and do best in a site with well-drained soil. The New England aster (Aster novae-angliae), one of the showiest of the fall-flowering asters, blooms from August to October. It has lavender, white, red, pink, or purple flowers and grows four- to six-feet tall with a three to five -foot spread. ‘Purple Dome’ is a popular lower-growing cultivar, only reaching about two feet high.
Boltonia (Boltonia spp.)
A close relative of the aster, Boltonia is also known as the “thousand flowered aster” because it produces many half-inch flowers on silvery, blue-green foliage, beginning in September. Use this plant, which grows from three to five feet tall depending on variety, in a meadow garden or at the back of a perennial bed. It likes moist, fertile soil and lots of sun. A popular variety is white Boltonia (Boltonia asteroides), which produces masses of white or pale purple flowers with a yellow center.
Goldenrod (Solidago spp.)
Don’t confuse goldenrod with ragweed. Although both bloom at the same time, it is the ragweed that is to blame for hay fever attacks, not goldenrod. This perennial has a plume-like bloom, consisting of many tiny clusters of yellow and golden-yellow flowers. It grows well in poor to average soil with good drainage in a site that gets at least six to eight hours of sun a day. The showy goldenrod (Solidago speciosa), a good variety for New England gardens, has soft yellow flowers on stalks from two to six feet high. If you want something different, try the low two-foot cultivars ‘Golden Fleece’ or ‘Fireworks.’
Helenium (Helenium autumnale)
This is also referred to as Helen’s flower, false sunflower, or sneezeweed. It is a prolific plant with many branched stems and numerous daisy-like flowers with raised, button-like centers. Colors range from gold and orange to bronze and maroon with dark centers. Helenium grows to three to four feet tall when grown in full sun and will produce flowers from late summer through fall. It likes plenty of moisture to bloom best, but well-drained soil. Most may need staking, but a newer low cultivar ‘Coppelia’ usually doesn’t.
Joe pye weed (Eupatorium)
This perennial with its eight-inch dusky pink and purplish flower heads and leathery green leaves is an excellent plant to grow to attract butterflies to the garden. Although it prefers moist soil and sun (even tolerating wet soils as by a pond or stream), it will tolerate drier soils and light shade. Because it can reach heights of six feet, it’s best planted in the back of the garden. ‘Gateway’ is one of the better cultivars to grow.
Rudbeckia (Rudbeckia spp.)
A favorite of many gardeners, rudbeckia or coneflower produces rich yellow-gold flowers with dark brown, black, or green cone-shaped centers and drooping petals. This perennial flourishes in full sun and well-drained soil although will tolerate most soil types. Plant in masses for a vibrant visual display that will last from July until frost. Plants grow from two to nine feet tall, depending on cultivar. ‘Goldsturm’ is the most popular cultivar, and one of the most popular of all perennials.
Sedum (Sedum spp.)
Another name for this fleshy-leafed, succulent plant with its flat-topped flower clusters of yellow, rose, or pink flowers is stonecrop. Although various cultivars bloom at different times throughout the season, some, like the ever-popular ‘Autumn Joy,’ produce flowers in late summer and fall, with the blooms and leaves changing color as the season progresses. Sedums make excellent edgings for borders. Some cultivars have variegated leaves, others solid colors such as bluish or red shades.
Toad lily (Tricyrtis)
A good perennial for partial shade and moist soil is the toad lily, which has clusters of pale, orchid-like flowers covered with pink, red, or purple dots. It grows to heights of up to three feet tall and flowers from mid- to late September until frost. Flowers are showy close-up, but not from a distance, so plants should be placed where easily seen as along paths. This plant is only hardy in warmer parts of our region (generally USDA zone 5 and warmer).
You also might like to include some of the ornamental grasses to add color, shape, and texture to the fall garden. Foliage may be green, bluish-green, or silver changing to beige or brown in late fall and winter. Some varieties have variegated foliage. Most are disease- and pest-resistant, adaptable to all types of growing conditions, and don’t require a lot of maintenance or frequent division as do a lot of perennials.
By Dr. Leonard Perry, Extension Professor University of Vermont
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PDF versionOrnamental Perennial Grasses
With the popularity of ornamental grasses and their use in the landscape, it is a good idea to understand how these plants grow. This understanding will lead to better use of these plants and often avoid disappointment or frustration.
Grasses respond and start to grow based upon temperature. Some grasses will start to grow in early spring when temperatures are still cool and others will wait until the soil is warm and temperatures are more stable.
Cool Season Grasses
Cool season grass will start to grow early in the spring and may even remain semi-evergreen over the winter. Cool season grasses also seem to do better and have better foliage quality when temperatures are cool or if they are given sufficient water during drought periods. If they are not watered during drought, they tend to go dormant resulting in brown foliage. These grasses may require more frequent division to keep them healthy looking and vigorous. If not, they tend to die out in the center. For the ones that remain semi-evergreen, you should only cut off the brown or winter injured foliage in the spring. Some of the more popular cool season grasses include, Fescues, Blue Oat Grass (Helictotrichon), Tufted Hair Grass (Deschampsia), and Autumn Moor Grass (Sesleria).
Warm Season Grasses
Warm season grasses will do better during warmer times of the year and remain good looking even when temperatures are high and moisture is limited. Warm season grasses do not begin to show growth until the weather becomes stable and the soils warm. The previous seasons growth usually browns out in the fall requiring the cutting back of plants to about 4-6 inches in the spring. Warm season grasses usually do not require as frequent division as cool season grasses. Some warm season grasses include Northern Sea Oats (Chasmanthium), Japanese Silver Grass (Miscanthus sp.), Hardy Pampas Grass (Erianthus), Perennial Fountain Grass (Pennisetum), Switch Grass (Panicum) and Prairie Cord Grass (Spartina).
Growth Habits
Before planting you should also understand the growth habit of the grass. Grasses can be either clump forming or rhizome forming. The latter is often called "running" grass. The clump forming grasses will grow in very nice, neat mounds or clumps. They tend to mix very well with other perennials and will not become invasive. They will increase in girth slowly over time. The rhizome forming grasses spread by underground stems and can become very aggressive and invasive. These grasses have their place but it may not be in a well-tended perennial border since they can soon take over an entire area. Before selecting a grass, be sure to understand how it grows so you won’t be planting a future problem. Some attractive but aggressive grasses include Blue Lymegrass, Cordgrass, and Ribbongrass.
Care and Maintenance
Fertilizer
Ornamental grasses require relatively low levels of fertility. By keeping the level of nitrogen low, lodging or flopping over can be kept to a minimum. Leaf color and vigor are good guides to nitrogen requirements. Application of one-half to one pound of 10-10-10 fertilizer per 100 sq. ft. of garden area or about one-quarter cup per plant is sufficient. Apply fertilizer just as growth resumes in the spring. An application of a slow release fertilizer such as Osmocote in the spring is enough to take care of the plant’s needs throughout the summer. Fertilizer should be watered in thoroughly.
Water
Plants should be well watered the first season after planting so they can develop a good root system. Established plants do not need regular watering, but may need supplemental watering during drought periods. The amount of water will depend on the grass species, the site, and on the quality, size and growth rate desired.
Weed Control
Cultivate around grass plants to control weeds. Application of mulch will greatly reduce the need for cultivation as well as watering. It also tends to keep grasses in check that have a tendency to be heavy reseeding types.
Winter Protection and Spring Clean up
Grasses do not need to be cut down before winter. In fact, they are attractive when left standing and the foliage helps to insulate the crown of the plant. Cut back the foliage to about 4-6 inches in the spring before growth resumes. When foliage is removed, spring growth will begin earlier. Old foliage left on the plant can delay the crown’s warming and subsequent growth by as much as 3 weeks.
Division
Division depends on the spacing and visual appearance of the plants as well as the overall health. Plants suffering from die-out in the center should be divided to improve appearances. Division is done in the spring before growth resumes or in the late summer or fall after the growing season. Plants that bloom late could be divided in the spring.
By Greg Stack - University of Illinois Extension Educator, Horticulture
Easy Care Perennials for Late Summer
Tue, 08/31/2010 - 6:52pm — Layanee DeMerchant
As summer winds down in late August and early September, the perennial border can look a bit sparse, a bit dry and a bit tired, but there are several sturdy perennials which can bridge the gap and add color to the border between the blooms of the daylilies and asters.
The following featured perennials are all drought-tolerant, full-sun plants that have the flowers of a supporting cast member rather than being sassy showgirls, although Helen’s Flower could qualify as a showgirl depending on your point of view. The flowers of this plant are small, about an inch across, but there are many and this plant stands a good four to five feet tall. Helenium autumnale is a vigorous clump-forming perennial. It does best in full sun and seemed to barely wink at the dry conditions of this August. It starts to bloom in late August and continues through the bulk of September. There are several cultivars to choose from at the garden center and their color ranges from deep mahogony through yellow. This plant is native to Eastern and north central North America and the butterflies and bees love it.
Leadwort or blue plumbago, Ceratostigma plumbaginoides, is a low-growing, spreading groundcover which tolerates dry conditions. Its blooms are electric blue highlighted by a reddish tinge of the stems. This plant could be used in a curb garden, in the front of the perennial border, or as a groundcover. Blue plumbago actually thrives in well-drained soil in full sun and its late blooming attribute only adds to its charm. Blue plumbago hails from China and is quite a hardy plant, growing well in Zones 5-9. I find that it does spread to a larger clump fairly quickly. I have underplanted it with spring-blooming Scilla siberica, which works well as the plumbago is late to emerge and leaf out. When the blue plumbago finally does send out leaves, the scilla is past bloom.
Calamint is a plant growing in popularity due to its low-maintenance attributes. It has small, glossy green leaves with upright stems and a stalk of tiny white to pale pink/lilac flowers. It hails from Southern Europe and has a minty fragrance when the leaves are bruised. 
It makes a great edging along a walkway in addition to blending into the border, where it remains shy until it is covered in flowers in late summer.
Hardy geraniums, or the cranesbills, are indispensible to the perennial border and there are over 400 species of hardy geraniums. There is a geranium for just about every different garden location and soil type, but one that has been developed and is used almost to the point of overuse is Geranium ‘Rozanne’. Can a plant which blooms for three or four months be overused? Probably, but this geranium is a welcome addition to any border. I find that in richer soil, Rozanne gets a bit gangly but with pinching and clipping, it produces a wonderful pinky purple flower all summer long. It can be a bit of a weaver with its blooms appearing above or entwined in other border flowers. That just makes it a great cottage garden plant. In average soil it remains quite well behaved, forming a good-sized clump with respectable flowers. 
‘Rozanne’ I include it because it received no special treatment this dry season and it is still loaded with blooms. Do you have any sturdy perennials to add to this list? Please feel free to share.
The Gardening Challenges of August
Fri, 08/20/2010 - 7:20am — Layanee DeMerchant 
This week, a friend came to visit my garden for the first time. It is always a treat to show someone around the garden but, I must confess, August is really not the best time for a showing at Ledge and Gardens. Her comment was ‘Your garden wears August well’. What a nice thing to say, especially to a gardener whose eyes have wearied of the view. I see the crabgrass gone viral in the lawn, wilting and browning foliage from drought, and a lack of color in the borders. It is very easy to have a colorful garden in May and June. The peonies and roses are at their best with full, lush blooms. August requires a definite plan. In August, the thick heavy air and languid heat combined with the rhythmic chirping of cicadas and crickets inspire this gardener to hit the lounge chair with a good book and that is as it should be.
Every gardener needs a bit of a break but the garden should always be a pleasure to view. It is difficult to plan for the changes nature imposes on us in the form of moisture or lack thereof. Each season has its own challenges and rewards and the garden responds accordingly. This year, August has been very dry, requiring a daily struggle with the hose. The coneflowers, Russian sage and hyssop have barely noticed while the phlox and astilbe have sulked and shriveled.
Hyssop Fortunately, planning can be done during the heat of these shortening days while any preparation, planting, or dividing of perennials can be done as the temperatures moderate in late summer and then be continued in springtime as the days lengthen. This season I did not mulch the gardens. Since last season was so wet, and the foliage of the garden perennials always fills in the gaps, mulch just seemed to be non-essential. This year, however, we have had a very dry August and mulch does help to retain moisture in addition to suppressing weeds. I think the garden would have suffered less with a layer of mulch and the plants would have been happier. Mulch also adds a layer of organic matter to the soil, improving it as it decomposes. Lesson learned, yet again.
I usually add annuals to my mixed borders to fill the gap. Some would say this is cheating. Hogwash! My garden, my rules. I like the color they add to both the border and the bouquet. Last year it was balsam, Impatiens balsamina, which is an old fashioned annual and one which blends well in a perennial garden. 
This year, I added zinnias and, to their credit, they seemed quite indifferent to the dry weather. Next year will include a wider variety of annuals for both color and texture in the August garden and they will include dahlias and cannas, which do extend the season, add bold foliage, and flowers for cutting. One more goal is to keep up with deadheading the perennials, which just helps to lengthen their bloom time. 
The bee balm has been continuously deadheaded and is still blooming as it has been since June, which the hummingbirds and bees also appreciate.
A garden can always be improved upon and that is one of the great joys of gardening. That said, it is also important to try to see your own garden through the eyes of another. One who has not seen it before and one who is obviously delighted to be invited into your imperfect sanctuary. That can be the ultimate satisfaction.
Delphinium Days
Fri, 08/06/2010 - 6:00am — Layanee DeMerchant
There are few perennials as stately and showstopping as the delphinium. This is the Delphinium elatum and subsequent cultivars which are the six foot plus delphiniums. These are a staple in many English borders. I say this knowing full well that English borders don’t always translate well to other parts of the world but if they do work at all in the U.S.A., it is in New England or, perhaps the northwestern U. S. I have found that one of the chief problems with delphiniums available to gardeners, both seed and potted plants, is their tendency to be shortlived. Much breeding has been done in the past century and many varieties such as the ‘Pacific Giant’ series are more annual than perennial. There are over three hundred species of delphinium and there seems to be as many named cultivars, making choices difficult. Seven years ago I sent for seed from the Royal Delphinium Society. The seed was expensive.
Given that and my tendency toward inattentiveness where seedlings are concerned, I gave the seeds to a grower friend who grew them on and gave me some plants in exchange for selling the rest of the seedlings. I have one plant which is sited in full sun and well drained soil which has bloomed consistently for the past seven years. It tops off at six and a half feet tall and is a rich, deep, royal purple. I have to believe that this seed was superior to most of the varieties which are more easily available in the seed racks and perennial benches.
There are a few ‘must dos’ with delphiniums. The primary one that I have learned is that delphiniums should be staked. Should is the operative word here. As gardeners we all try to find the time to get all the basic chores done but some, inevitably, fall by the wayside. I have staked this plant in the past but for the last few years it has flowered on thick stalks which seem so very sturdy when they are developing. They are sturdy until the flowers open from the bottom of the spike upward to the last dancing dolphin bud. The volume of the flowers can catch the wind and the rain of a sudden thunderstorm and in just a few moments of unbridled nature’s passion, those six foot spikes bend and break along with one’s heart. Heartbreak which could be avoided.
Last year the delphiniums looked like this and this year the gardener has once again been taught a lesson as the delphinium takes the fall.
The delphinium received its name from the Greek word delphis which means dolphin. 
The delphinium flower has a characteristic spur on the back of the flower and flower bud which does look a bit like a swimming dolphin or a school of dolphins, especially if one squints.
If you have ever seen rows of delphiniums such as these in the trial gardens at Wisley in England, 
Wisley Trial Gardensyou will be unable to resist the urge to try a few in your border. Site them in an area of full sun, rich, well drained soil, and out of reach of strong winds. It is important to site the plants correctly as established plants do not transplant easily. Delphiniums do prefer neutral pH but they will tolerate slight variations from neutral. Compost is a great addition to the planting area as delphiniums are heavy feeders.
Do you have delphiniums in your garden? I am currently trying to devise a better staking method than bamboo stakes and string which always looks unsightly. If you have a better staking method to share, please share it here.
Ferns
Ferns provide a great feeling to any landscape. Despite their delicate appearance, they’re actually quite durable and require very little maintenance.
They work well in shady spaces and their reliable foliage provides a constant presence in your yard unlike other plants that will bloom and pass. Their natural look and feel is typical of most woodland plants but there’s an amazing diversity of textures, habits and colors from one variety to another.
Our extensive selection of perenial ferns includes many shade and sun tolerant varieties, as well as many ground cover and shrub-like varieties. So why not try something new this season?
Perennial Gardening for Beginners
All too often gardeners are hesitant to work with perennials. Their different bloom times and multiple varieties may seem daunting. However, most perennials are easy to grow and offer years of pleasure for your investment. You will need to see perennials as a trade off. Instead of blooming all season like an annual, their bloom time is shorter so they can come back to do it again. Remember that because perennials don’t bloom all season like annuals, other characteristics of the plant become important (such as shape, texture, and foliage color). Annuals and perennials complement each other, so use them together.
Here at Mahoney’s, we pride ourselves in our extensive collection of perennials. We’ve got everything from sun loving and shade tolerant to fantastic groundcovers and eco-conscious Native perennials.
What is a perennial?
A perennial is an herbaceous plant that lives three or more years. Herbaceous plants die back to the ground each winter. Most perennials are grown for blooms, but there are those (such as lamb’s ear, hosta and artemisia) that are grown for the beauty of their foliage. The life span of various perennials can range from just a few years to decades
Where should I use perennials?
Almost anywhere. Perennials are probably the most useful, versatile plants around. Use them in beds, borders, with evergreens, in containers, in cutting gardens or anywhere you need them. There are perennials suitable for almost every site, from hot and dry to damp and shady. Just ask our expert staff!
How do I choose which perennials to plant?
The site itself is the most important element in choosing the right perennials. Do you have sun or shade? What is the soil like? After that, the most important is bloom color and season. At Mahoney’s, our vast selection is sure to impress. Our knowledgeable experts are here to assist you.
When should I plant perennials? Almost anytime! Since most are now grown in containers, they can be planted throughout the growing season. When planting during the hot part of the season, be sure to provide extra water until the plant has had a chance to root out.
How do I plant perennials?
Easy! Perennials are resilient and require no additional planting instructions. Like annuals, perennials require a nutritious soil composition for optimum performance in your yard. Just be sure to keep them at the same level at which they were growing in the container.
Do they require any special care?
Just like all your other plants, they will need fertilizing. Check occasionally for disease or insect problems. Deadheading (removing spent blooms) will often extend the blooming season. After a killing frost in the fall, remove all the dead foliage. Most perennials will benefit from being mulched for winter protection late in the fall.
What about dividing?
Almost all perennials will perform best if divided every 3 or 4 years. Some of the more aggressive growers can be divided even more often, and others (like peonies) less often, or never! Most reference books will tell you which varieties prefer to be divided or talk with a member of our expert staff.
Native Perennials
Plants native to the Northeast offer a vast array of colors, shapes and textures. With beautiful displays of flowers and foliage, native perennials make great additions to any New England garden, but beauty and variety aren’t the only reasons why.
Low maintenance
Aside from regular watering during their first season, most native perennials require little maintenance. In general they’re resistant to disease and insects and do not require fertilization or protection in the winter.
Adaptable
Because soil types, light conditions and temperatures change so rapidly and vary so much throughout this region, many native perennials are able to survive in wide range of conditions.
Hardy
They are naturally occurring in the local environment so they actually thrive even after the harshest New England winter.
Good for local ecology
By planting native plants, you are restoring part of the natural ecology that is slowly being overtaken by the invasive offspring of non-native species. Also, they help support the population of native animals, by supplying a food source as well as shelter.
Try these native perennials
Cornus Canadensis
Also known as Bunchberry; Most gardeners know Dogwoods as trees or shrubs, but this species produces short creeping plants that are delightful at the front of a shade garden. The familiar white, four-bracted flowers face upwards and are followed by beautiful red berries. A dependable northern native.
Echinacea
Also known as Cone Flower; has big, bright flowers that appear in late June and keep coming into September. Plants thrive in average soils or hot, dry conditions, shrug off cold, and are equally at home in full sun or partial shade. Perfect for cut flowers in bouquets.
Baptisia
Also known as False Indigo. They look attractive on their own against walls and fences, or combined in a border with other June bloomers. In full sun, these plants can be extremely long lived.
Asters
A late bloomer requiring full sun, the aster is the tell-tale sign that fall is on its way. They come in a wide variety, with some less than a foot tall, while others are two feet tall or more. Both large and smaller varieties make good cut flowers for vases and arrangements.
Bee Balm
Also known as Monarda; bee balm is a genus of several native species, all of which share tartly fragrant foliage and the square stems that typify the members of the Mint family. The late-summer flower heads are hemispheres of tubular blooms in brilliant colors. Plants thrive in full sun or partial shade and evenly moist soil.
Butterfly Weed
An extremely hardy, long-lived perennial native to North America. The magnificent bright orange flowers are concentrated in compact clusters at the top of branching stems. The flowers produce a large quantity of nectar which attracts butterflies throughout the growing season. Requires a very well-drained sandy or gravelly soil in full sun.
Cardinal Flower
Strong, upright stems bear dozens of brilliant red flowers in late summer. A favorite source of nectar for hummingbirds. Also excellent for attracting butterflies. Grows well in standing water or moist garden soil. As soil moisture increases, so does sun tolerance.
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