Perennials

We sell hundreds of salvia plants each year, and with good reason.  Meadow sage is a dependable perennial plant that comes back year after year.  Their spikes of purple, blue or white flowers shoot up from the foliage in early summer, lasting for more than a month.  The rabbits don’t seem to touch them, and deer mostly
leave them alone because of their pungent smell and slightly hairy leaves.

Plant them in  average, well-drained soil in a sunny spot.  Care is also easy:  after the frost, cut down the wizened foliage.  To keep the plant looking fresh all season, cut the spent flower spikes back to the basal foliage in mid-summer.   Many cultivars will reward the gardener with a second flush of bloom.

During our recent trip to Connecticut to visit one of our growers, I was excited to see fields and fields of Salvia in bloom.  It was the perfect opportunity to make a collage comparing them.  Their attributes are listed below, along with the collage.

‘Blue Hill’:  Dense spikes of true blue flowers.  1.5 – 2′ tall.  Blooms June-July.

‘Snow Hill’:  White flowers on compact plants.  1.5′ tall.  Blooms June-July.

‘Marcus’:  Deep blue flowers on dwarf plants.  8-12″ tall.  Blooms a week or more after other cultivars.

‘East Friesland’:  Deep violet flowers.  1.5′ tall.  Blooms June-July

‘Mainacht‘ aka ‘May Night’:  Dark purple flowers.  1.5′ tall.  Blooms June-July.  Dependable re-bloomer.

‘Cardonna’:  Black flower stems, violet flowers.  2-2.5′ tall.  Blooms May-July.  A personal favorite.

-Brad MacDonald

Alchemilla

Lady’s Mantle is one of the most common perennials in Nantucket gardens for good reason.  These charming plants are incredibly reliable, rabbit and deer resistant and have loads of flower power over a long period.  They look spectacular in early summer when the plant is covered in chartreuse-yellow flowers.  The tiny star-shaped  airy flowers look just as well in a cut flower arrangement as in the garden.  When not in flower, the fuzzy
foliage is also lovely.  In the morning, the leaves are covered in drops of dew that sparkle in the sun.

These plants blend equally well with sun and shade combinations.   Plant them as a low edging along a shady path with ferns as a background or in the front of the perennial border with catmint or small grasses.  Alchemilla likes a spot with average soil and even moisture.  In my experience, the foliage holds up the best in plantings that have some afternoon shade.

Maintenance is easy.  Once the flowers have begun to turn brown, remove them.  There are a few ways to do it;either shear back the entire plant, allowing the basal foliage to grow and fill back in, or cut or pull the stalks away from the base  of the plant.  While dormant, cut back the foliage to the ground.

Some of the most common species and cultivars are listed below:

• Alchemilla mollis:  The most common species of Lady’s Mantle.  Leaves are 6″ wide.  Flowers tend to fall toward the outside of the plant when in full bloom, forming a mantle or skirt – hence it’s common name.  18″ tall to 24″ wide.
• Alchemilla mollis ‘Thriller’:  Slightly larger than the species, possibly with even more flowers. 18-24″ tall and wide.
• Alchemilla mollis ‘Auslese’ aka ‘Select’ and ‘Robustica’:  A dwarf form.  Compact plants hold flowers in a more upright fashion than other Alchemilla mollis cultivars. 12″ tall and 18″ wide.
• Alchemilla sericata ‘Gold Strike’:  A compact species, 14″ tall.  Medium-sized, deeply scalloped leaves.  Flowers tend to stay upright.
• Alchemilla erythropoda:  The smallest species of Alchemilla that is readily available.  Perfect for a tiny garden.  6-8″ tall.

Russian sage is a fantastic plant for us on Nantucket, having all the qualities we look for in a great perennial:

• It’s hardy, overwintering easily without any special coddling needed from the gardener
• It performs best in the lean, sandy soil that most of us have on the island.
• It’s aromatic grey green foliage has just enough fuzz to make it very deer resistant
• It has a long season of interest, looking great from June through October
• It flowers for a very long time in mid to late summer, when seasonal residents are on the island.
• Its lacy leaves, blue flowers and open habit make it quite versatile in the landscape.  It can be added to perennial gardens, makes a dramatic mass planting and pairs extremely well with ornamental grasses.

Although many of us have been taught to leave Russian sage standing and prune it in spring, I’ve also had perfect results pruning it in fall, when I cut down my spent perennials.  Just be sure to wait until it is dormant, preferably after a frost.

Objectives for pruning Russian Sage are:  Removing dead twigs, removing broken or damaged branches, stimulating strong growth from a balanced framework of stems that will flower the following summer.

Follow these steps to prune Russian Sage while dormant:

1. Cut back all growth from the past season to healthy buds, within 6-8 inches from the soil.
2. Remove any dead branches as well as broken or damaged wood.
3. Remove any skinny twigs incapable of supporting strong new branches next season
4. If possible, cut back a few of the oldest stems close to the soil, to encourage strong young shoots to replace the older ones.

Now that we know the right way to prune Russian Sage, I’ll let you in on a little secret. This plant is extremely forgiving; most landscapers on the island use the “Hair Cut” method of pruning.  Just gather up the twigs in one hand and prune them all off evenly with the other.  Or, if you prefer, take to them with your hedge trimmers!   New growth next summer will quickly cover any dead twigs remaining.

September on Nantucket is punctuated by a few really special plants. One of these is Clematis paniculata. Although this species of clematis does have a reputation for being somewhat aggressive, many gardeners consider it well worth the time spent pruning and tying.

Sweet Autumn Clematis bursts into growth in spring and will easily grow to cover a story-tall trellis in a season. It is beautiful trained along a fence, or up a pergola or down spout. Or let it sprawl along the ground in open areas as a ground cover. Plant it in full sun to part sun in average soil and this clematis will reward you with dark green growth all season and thousands of delicate white flowers in September. Even the soft, silvery seed heads are attractive, after the flowers fade.

Here are a few pointers to get the most out of Sweet Autumn Clematis in the Garden:

• Cut back Sweet Autumn Clematis to within a foot of the ground each year while the plant is dormant. Unpruned stems left to mature for years will become woody and leafless. As well as being unattractive to look at, these stems will not produce new growth or flowers. Unpruned vines will only flush out at the top, producing a weird top-heavy appearance.
• Take the time to train the clematis as it grows. Clematis do not cling with tendrils like other vines, their leaves actually twist around supports to climb. This habit requires a little tying now and then to help it cover the support neatly. If kept tight to the support, the rangy look that these plants can develop is obviated, and they take on a more stately appearance.
• If used as a ground cover, be sure to pin or trim it around other ornamentals. These vines can quickly cover and smother adjacent plants.
• If any seedlings appear in the garden, pull them up when they are young. The longer volunteers are left to establish the more difficult they are to remove.

August is often a tough time in the garden, here on Nantucket. Weeks of hot, humid and windy weather can really take a toll on the flowers we work so hard to grow. Who wants to be out deadheading and staking Cosmos, when you could be at the beach, anyway? Get your flower fix from Nantucket’s Native Garden! The magnificent show of Rose Mallow’s tropical-looking flowers along the islands wetland areas is more than enough for me! If you haven’t seen the mass of pink flowers next to the Bamboo Forest on Madaket road, slow down on the way to the Landfill this Sunday, you won’t be disappointed!

We sell a wide range of Hardy Hibiscus here at the Nursery. The enormous dinner plate-sized flowers are a customer favorite. There are white, red, pink, and even bicolor selections! New gardeners are surprised that such a show-stopping flower is incredibly easy to grow. Plant it in full sun in evenly moist, somewhat fertile soil, you won’t be disappointed each August.

A few points to remember when growing Hardy Hibiscus:

•New shoots from Rose Mallow are very late to show in the garden. When you cut them back in the winter, leave the spent stalks a foot tall, so that you know where they are, and don’t trample them as you work in the garden early in the season.

•These are plants that naturally grow next to wet areas. If they dry out, they will lose leaves in a hurry. Keep them evenly moist!

•If you find your plants tend to get leggy or only produce a few shoots each year, give them a light pinch early in the season and they will branch out and have even more flowers for you.

One of the most common questions we get about clematis at the nursery concerns pruning.  To be honest, it’s confusing, so any questions are valid.    The most important factor in deciding how to prune clematis is placing them in the right category.

Vining clematis is separated into three main categories, A, B and C.

GROUP A:

• Vines that don’t die back in winter and bloom in the spring
• Includes C. montana ‘Rubens’ (Pink) and C. montana ‘Alexander’ (White)
• Since these bloom on old wood, major pruning should be left until after they flower in spring.
• If there is obvious deadwood, it can be removed earlier in the season; make final cuts just above live buds.  Keep in mind, removal of live branches will also remove overwintering flower buds.

GROUP B:

• Vines with large flowers, or doubles, often reblooming.
• Incudes C. ‘Henryi’, C. ‘Nelly Moser’ and other stunning varieties.
• These plants bloom on old wood in spring and in later summer on new wood, so pruning should be kept to a minimum, no matter the time of year.
• Limit pruning to removal of dead branches, and tie live branches, evenly, across the trellis

GROUP C:

• Includes a wide assortment of varieties.  C. viticella ‘Betty Corning’ C. paniculata ( Sweet Autumn Clematis), C. ‘Jackmanii’ and C. ‘Niobe’
• These are the easiest to prune.  Cut the entire vine down to within a foot of the ground leaving 2 to 4 sets of buds.
• If you aren’t sure if your clematis is in this group, try leaving it alone for a season.  If it dies to the ground over the winter, or flowers only at the top with loads of dead foliage and bare stems at the base, it’s likely in this group.

The scent of lavender carries a certain nostalgia for many people.  Maybe it’s the smell of grandmas dresser drawers or moms perfume?  Happily, lavender is easy to grow, given the right conditions.  So, we can recreate that scent memory in our gardens.

• L. angustifolia ‘Hidcote’:  Dwarf English lavender.  Named after Hidcote Manor in England.  Grows to a foot high, with flower stems to 18″.  Deep purple flowers.
• L. angustifolia ‘Munstead’:  English lavender.  Named after Munstead Woods in England, home of famous garden designer Gertrude Jeckyl.  Grows to a foot high, with flower stems to 20″.  Flowers are much less violet than ‘Hidcote’, decidedly blue.
• L. x intermedia ‘Provence’:  French hybrid lavender.  One of the cultivars grown in France for the commercial lavender industry.  Touted as being more tolerant of wet feet than others.  Tall flower stems reaching 30″.
• L. x intermedia ‘Grosso’:  French hybrid lavender:  One of the best for cutting.  Stems grow to 30″.