Tag Archives: low maintenance perennials

Conoclinium coelestinum ‘Cory’

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A new name for the Hardy Ageratum. Formerly Eupatorium coelestinum, the plant taxonomists have bestowed the name Con-oh-clin-i-um on this late summer into fall blooming plant. The species name co-el-est-in-um means heavenly. Clusters of heavenly sky blue flowers atop 18-30″ stems bloom in August and September, attracting butterflies and pollinators. Conoclinium enjoy average, evenly moist soil conditions and spreads by stolons, creating a healthy patch where happy. It makes a lovely cut flower and is hardy in zones 5-8.

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Allium ‘Millenium’

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Allium ‘Millenium’ in the early morning light.

What’s not to love? This Allium hybrid from Mark McDonough is one of the key plants for solid bloom in July and August in our perennial and mixed beds. 2″ lavender orbs on sturdy 12-18″ stems provide color for weeks. It doesn’t mind the heat and dry soil, and  bulks up quickly, and can be divided in the spring if you want to spread it around. Of course it is attractive to butterflies and pollinators. When blooming fades, cut back the stems, or leave the heads on to dry and add textural interest. Deer and rabbit resistant and it is perfectly hardy in zones 5-9.

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Smitten by Solomon’s Seal

Polygonatum x hybridum 'Striatum'

Polygonatum x hybridum ‘Striatum’

Unfurling

Other forms….Unfurling

Dancing

Dancing

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Dangling

Just a few images to share….loving the various species and  forms in the genus Polygonatum (Solomon’s Seal).  We currently have about 15 selections, ranging in size from tiny 6″ Polygonatum humile to  6′ selections of P. biflorum. and are always seeking out more.

quick facts: Solomon Seals is in the family Asparagaceae. Most forms are hardy in zones 5-8, (a few in zones 3 & 4). They slowly spread by jointed rhizomes, and enjoy well drained soil in partial to full shade. Long lived and almost indestructible, Solomon’s Seal is one of those plants that holds its good looks with little care all season.

Asparagus Ferns to Know and Grow

Perhaps your grandmother had a big hanging basket of Asparagus Fern on her shady porch…you probably didn’t think much about it, but there it lived, thriving with little care, living in the same pot for what seemed to be years on end. Yes-sir-ree…a testimony to a plant which could thrive on neglect.

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Just planted….Asparagus setaceus plumosa, with 2 begonias in an 8″ square pot.

Despite their fernlike ambience, this group of foliage plants are not ferns at all, but members of the Lily family (Liliaceae). An inspection of the root system reveals a mass of bulb-like tubers, (think lily bulbs). Being pot bound doesn’t discourage their vigor and although they like bright light, Asparagus Ferns can exist satisfactorily with quite a bit of shade. They do not need a constant supply of moisture, and prefer a soil that is sharp draining. Take note: Asparagus Ferns make great companions to Begonia  which like similar conditions… bright light to shade, and a soil that doesn’t stay wet.

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Asparagus densiflorus ‘Sprengeri’ (L) and densiflorus ‘Myersi’ (R)

The most familiar species is A. densiflorus ‘Sprengeri’, known for it’s arching stems of apple green narrow leaves. (For those who need to be on top of all things botanical…the genus is now Protasparagus, but that may be too much information for some. ) The next most commonly encountered form is the Foxtail Asparagus, A. densiflorus ‘Myersi’, with its  gorgeous chunky plumes.

Now, let me introduce you to  a few siblings, which offer variety but require the same easy care, and of course are suitable as cut greenery for arrangements.

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Clockwise from upper left: A. densiflorus ‘Cwebe’, A. setaceus plumosa, A. setaceus pyramidalis, and A. macowanii

Asperagus densiflorus ‘Cwebe’ is not dissimilar to Grandma’s form, but ‘Cwebe’ tends to be more upright, growing, to 18-20″ tall, and has an interesting bronze tint to the new growth. Asparagus setaceus plumosa is  very lacy,  and is familiar to those who purchase cut greens for arranging.  Asparagus setaceus pyramidalis also has lacy, fine textured foliage with an upright thrust. Perhaps the sweetest of all is Asparagus macowanii, commonly called Ming Fern, with very delicate forest green foliage. As a young plant A. macowanii  is quite small in stature, but if grown in a conservatory or outdoors where it is hardy, it can reach a height of 5’ at maturity.

5 Fall Bloomers for Shady Gardens

Actaea simplex 'Hillside Black Beauty'

Actaea simplex ‘Hillside Black Beauty’

What’s black (dark chocolate) and white (ivory) and smells like grape jelly? Answer: Actaea simplex ‘Hillside Black Beauty’, formerly categorized as Cimicifuga and commonly known as Fairy Candles (yes!) Bugbane (eee-uugh!), or Cohosh. This selection originated years ago at Fred and Maryann McGourty’s famous Hillside Gardens in CT. Select this plant for its brown/black foliage which is attractive all season. In September, fragrant  ivory flowers on 5-6′ stems emit a smell reminiscent of my childhood… Welch’s grape jelly. Actaea like a soil that has even moisture, and will need supplemental watering in dry spells. Hardy in zones 5-8.

Tricyrtis 'White Towers'

Tricyrtis hirta ‘White Towers’

Toad lilies  have their charms….exquisite, up close and personal blossoms, sometimes lavender, sometimes purple spotted…Tricyrtis ‘White Towers’  has pure white blossoms which lack spots, but are accented with lavender tinted stamens. The upright somewhat arching stems grow 18-20″ tall, and plants spread by stolons. Toad lilies like an evenly moist soil as well, and are hardy in zones 4-8.

Hosta 'One Man's Treasure'

Hosta ‘One Man’s Treasure’

More attention should be paid to Hosta with showy flowers, especially when they bloom at the end of the summer. Hosta ‘One Man’s Treasure’ is a small to medium Hosta with simple dark green leaves that have distinctive reddish purple petioles. In late September  clusters of showy dark lavender flowers are produced.  Hardy in zones 3-8.

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Aralia cordata ‘Sun King’

Aralia cordata ‘Sun King’ , commonly known as Spikenard, has bold compound leaves which are bright yellow when grown in a lot of sun, and  more of a chartreuse if given more shade. At first this plant seems unimposing, but give this Aralia a few years and it will be super sized…a good 5-6′ tall and wide. White starbursts of flowers form in September on dark stems followed by black fruit. Hardy in zones 4-9.

Begonia grandis 'Heron's Pirouette'

Begonia grandis ‘Heron’s Pirouette’

Pretty enough to be grown as a container specimen, yet Begonia grandis perpetuates for us in well drained soil, especially in pockets at the top of our retaining wall. Plants are propagated by dividing little bulbils which form underground as well as along the stems.  The attractive ovate leaves are under-sided in a ruby red ,  and from August to October sprays of  dainty pale pink flowers are born on 18″ upright then decumbent stems. Please note that in the spring, plants don’t show signs of like until late May here in New England, so mark the planting spot to prevent plants from accidentally being dug up. Hardy in zones 6-10.

 

The Other Hardy Hens & Chicks

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Jovibarba heuffelii with small Sempervivum, Echeveria & Orostachys in the background.

The most familiar hens and chicks are in the genus Sempervivum. I’d like to introduce you to the  less familiar with same common name which are classified in the genera Jovibarba, Orostachys and Rosularia.  All are members of the Crassulacea family.

A rosette of Sempervivum flowering

A rosette of Sempervivum flowering, but with a number of offsets surviving.

Like Sempervivum, all are monocarpic, which means when the main rosette erupts into flower, it will set seed and cease to exist. (You can see why it is a good thing that many offsets of new plantlets have been freely produced.)

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Jovibarba hirta ssp arenaria

The genus Jovibarba is sometimes classified as a sub genus of Sempervivum.  Jovibarba is distinguished by blossoms bearing pale green to yellow 6 petaled flowers compared to Sempervivum’s 10-12 petaled pink blossoms. There are only 3 species in the genus: globifera, hueffeli and hirta. J. globifera and hirta freely produce stoloniferous offsets but  J. heuffelii’s “chicks” are tightly attached to the crown, and need to be severed to propagate more babies. J. hirta ssp arenaria  forms dozens of delightful miniature rosettes (1/4-3/4”) of pale gray green leaves covered with tiny hairs. Cool temperatures bring out red foliage highlights. Grow in a lean soil with sharp drainage in hardiness zones 5-9.

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Orostachys spinosus

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Orostachys minutum

Orostochys is a slightly bigger genus…it includes the more popular O. iwarenge (Dunce caps) as well as several others that are garden worthy subjects. The mature rosette of O. spinosus gives the appearance of a silver sunflower with an array of silver quilled foliage surrounding a center of congested tiny tight leaves. It is hardy to zone 4-9, but requires very well drained soil. O. minutum (also listed as O. spinosum minutum) is quite petite as the specific name suggests, producing clusters of 1/2-1” rosettes of blue gray foliage. It  would make an excellent alpine trough plant.

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Rosularia muratdaghensis

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Rosularia serpentinica

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Rosularia chrysantha

The genus Rosularia includes about 35 species. We have grown R. muratdaghensis, R. serpentinica, and R. chrysantha. Both R. muratdaghenis and serpentinica form tight mounding rosettes of gray green foliage, accented with red tones in cooler temperatures. R. chrysantha has a mat forming habit,with rosettes of soft velvety green leaves. All 3 species demand lean soil with excellent drainage and are are hardy in zones 5-9.

Persicaria polymorpha

Persicaria polymorpha at dusk, photo by Paul Clancy

Persicaria polymorpha at dusk, photo by Paul Clancy

Mention the name Persicaria in horticulture circles, and you may raise a few eyebrows. Persicaria has a very bad cousin: Polygonum cuspidatum, commonly  known as Japanese Knotweed or Running Bamboo (but it is not a bamboo!), and this cousin can spread DREADFULLY. But please read on…

Persicaria polymorpha is commonly called Giant Fleece Flower, and this common name  describes it well. Within a few seasons, Persicaria polymorpha will reach 5′, maybe 6′ tall and form imposing clumps, increasing in width each season to 6′ or more. Talk about taking up space! In June and July, white Astilbe like plumes adorn the plant and the blooms seem to last and last. This is a great plant for a long distance view (think about its size and white color) and is memorable when viewed in the early evening light.

Here are the facts: Giant Fleece Flower likes average soil, or moist soil, or even very dry soil once established. It loves full sun but will grow in partial shade. It is a bold perennial and and adds contrast to the finer textured plants in your garden. Like Baptisia, it is one of the first herbaceous plants to attain good height in the spring.  It is deer resistant and long lived. I have yet to discover seedlings about, although it can be propagated by seed. Persicaria polymorpha is hardy in zones 4-9.

Consider Persicaria polymorpha when you are in need of a big, bold, hardy, long blooming, deer resistant plant.

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Kalimeris incisa ‘Blue Star’

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Kalimeris incisa ‘Blue Star’ at Avant Gardens

As much as I am wowed by voluptuous blossoms, I like to champion the strong garden performers which have quieter charm. One whose charm seldom disappoints is an Asian Aster relative called Kalimeris incise ‘Blue Star’. This little number grows 15-18″ tall and 18-24″ wide, and begins its production of 1 1/2″ lavender blue daisies in June, carrying on into autumn (I kid you not.) ‘Blue Star’ forms tidy clumps; it does not run, unlike some of the other Aster relatives that we have tried such as Asteromoea and Aster ageratoides.  Use Kalimeris incisa ‘Blue Star’ in the front of the border, paired with other favorites, such as Calamintha nepeta sp nepeta, Persicaria amplexicaulis ‘Firetails’ and Hydrangea paniculata ‘Little Lime’ for an easy  long blooming ensemble.

Grow ‘Blue Star’ in full sun in a soil that has good drainage, and it doesn’t hurt to thank this star performer with a liquid fish emulsion fertilizer a few times during summer.  It is hardy in zones 5-8.

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Calamintha nepeta ssp. nepeta

Calamintha nepeta ssp. nepeta

At last, we found an image that displays Lesser Calamint,Calamintha nepeta ssp. nepeta , in a flattering light. Perhaps that’s why more people don’t grow it: it doesn’t always photograph well, and it’s not in bloom when everyone is plant shopping in April and May. It has been one of our “go to” plants when designing sunny gardens for years. Here’s why.

Calamintha nepeta ssp. nepeta has grown well in our garden for the past 18 years. Yes, the same specimens, planted in 1995, return each year true to form. In spring they present as tidy little subshrubs (no, it does not spread by runners) with mint scented, slightly shiny leaves.  In July (June in warmer zones) sturdy 18″ stems bearing racemes of airy blue tinted white flowers appear, creating a cloud like effect for the front of the border and accenting any plant around it, and it is especially complimentary to roses. The blossoming continues into October, when the flowers take on blue tones with cooler temperatures.  Calamintha nepeta ssp. nepeta is a primo plant for attracting bees, butterflies and beneficial insects. This form of Lesser Calamint has rarely self sown in our gardens, unlike the very similar  Calamintha nepeta ‘White Cloud’, which seems to happily self sow. You might like having babies, or not. You decide.

As mentioned before, this is a reliable perennial (18 years and still going strong) for us here in southern New England. Calamintha nepeta ssp. nepeta performs well whether we  are having a hot dry summer or a cool moist one. It likes a soil that is well drained, but does not need or want lots of fertilizer. I know it will be this reliable in zones 5-7, but would be interested in hearing if folks are growing it successfully in zones 8 and 9.  Its tidy form and endless flowering means it can be combined with so many other plants, depending on your color scheme, but consider using it with Asclepias tuberosa, Sedum ‘Maestro’, Echinacea ‘Fatal Attraction’ or Caryopteris for strong summer interest.

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In Praise of Baptisia

Baptisia ‘Twilight’ adding height in the background, with Allium and Euphorbia

I often like to tempt you with plants which I suspect you may be unfamiliar with, but a walk about the garden convinced me to laud praise on our garden stalwarts. In particular I’d like to reacquaint you with my old perennial favorite, Baptisia, and its recent reincarnations.

Baptisia, commonly known as False Indigo or False Lupine, was one of the perennials we planted in our first garden 25 years ago, and that same B. australis, introduced as a young seedling, still surges forth each spring with vigor and good looks.  Baptisia is not a only long lived plant, it is also one of the first perennials which add height to the late spring border, shooting up to and eventually forming clumps of 3? or more. The early size factor adds greatly to it?s value. The flowers are displayed on showy spires and resemble lupines. It is a great compliment to the other late spring stars: Peonies, Iris, Euphorbia and late bulbs like Allium.

The most common species you’ll encounter is B. australis, with typically violet blue flowers and a height of 3-4′ and equal width. Other species you may commonly encounter include B. alba, (with white flowers) and B. sphaerocarpa (yellow), and to some extent B. bracteata. In recent years hybrids have been made crossing the species, alternating host and pollen plants. Ron Gardner introduced ‘Carolina Moonlight’ after  successfully crossing B. alba and B. sphaerocarpa in 2002.  Jim Ault of the Chicago Garden has developed a number of great cultivars by crossing B. australis and sphaerocarpa resulting in named forms B. ‘Solar Flare’, ‘Twilight, and Midnight Prairie Blues’. Hans Hansen has developed more crosses are becoming available such as ‘Lemon Meringue’and ‘Dutch Chocolate’.

Baptisia ‘Midnight Prairie Blues’

Baptisia ‘Solar Flare’

A form we grow in our gardens which always draws comment for it’s compact habit is Baptisia australis var minor. It forms a low 2”mound of dense blue green foliage with typical large blue violet flowers, but long after the flowers fade, B. australis var minor  shows off with its tidy appearance . Another excellent but slow growing form is a selection made by Brian Megowan of the legendary Blue Meadow Farm: B. ‘Esther’, with her white flowers born on dusky slate stems. We’re rooting stem cuttings of her now, in hopes of having young plants for sale next spring.

Baptisia australis var minor

Baptisia ‘Esther’

Some things to note. Baptisia are prairie plants and like a sunny well drained soil. Baptisia australis is the hardiest of the group, tolerating cold zone 3 winters. Baptisia alba and sphaerocarpa are hardy through zone 5. The hybrids seem to fall right in the middle with hardiness tolerance of zones 4-9. Baptisia species can be grown from seed, but her clones are vegetatively propagated. Baptisia develop deep tap roots, so division isn’t easy, although it can be done, but expect some die back and a slow recovery.