The Truth about Hollyhocks

Hollyhocks (Alcea rosea) are an old-fashioned staple flower of the cottage garden and a favorite of island gardeners. Stately plants with spires of flowers up to six feet tall grace the back of the border or adorn white picket fences.

Flowers may be single, double, pastel, or saturated, sometimes even bicolor. In perfect growing conditions, they grace the garden for six weeks or more, as flowers open continually up the stalk while the mature ones fade toward the bottom. Because they are biennial plants, during their first growing season they do not flower, rather they form a basal rosette and store energy for the upcoming summer. During the second year, they flower, set seed and die.

Self-seeding is generally sufficient to keep a garden filled with flowers year after year. To be absolutely certain, the nervous gardener will collect seed in September that has ripened on the plant and grow out seedlings right away. Allowing the seedlings to overwinter in a protected area forces the plant into a bloom cycle when growth resumes. Ta Da! Flowers from year to year.

All that said, experienced gardeners already know the DIRTY TRUTH about hollyhocks. Hollyhocks are riddled with disease and insect pests! Rust is Real! Snails are horrible hollyhock eating monsters! If your plants make it to flowering with any leaves at all, INCOMING!!!!! Japanese Beetles cover the plants quickly devouring all that remain! Ok Ok, so you can definitely Sluggo for the slimies, and you can spray insecticide for the avian invaders, but what can you do about rust?

 

Hollyhock RustHollyhock Rust (Puccinia malvacaerum) is a fungal disease effecting leaves and stems of many plants in the Malva family. Rust is NOT avoidable. Fungal spores are present in the soil, on non-host plants and leaf litter. They are tiny and light enough to be blown hundreds of miles from their point of origin. Once the spore lands on a damp hollyhock leaf, it germinates almost immediately, and infiltrates the leaf’s tissue. As the fungus grows inside the leaf it damages the healthy plant cells, weakening the leaf and disrupting photosynthesis. The rust completes its life cycle quickly and causes orange pustules to erupt on the surface of the leaves. Spores are released from these pustules and infect more plants.

 

Control measures may be helpful, but will not stop the infection from occurring. Be sure to clean up the garden very well in the fall. Making sure there is no residual hollyhock leaf litter that may harbor spores is a good start. Try applying wetable sulfur early in the season, to create an inhospitable environment for the spores to grow in. Continue to spray the plants as new growth emerges. Allow good spacing between plants to speed drying of the leaves after morning dew. When leaves do become infected, remove them. Most importantly, plant tall, late season perennials in front of your hollyhocks to mask their foliage. Phlox works well, as do Montauk daisies.


How to Prune Russian Sage

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.
Russian Sage before pruning
Russian Sage before pruning

Perovskia atriplicifolia healthy dormant buds-1

Perovskia atriplicifolia post pruning-1

 

 

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.


Sweet Autumn Clematis

Clematis paniculata - Sweet Autumn Clematis flowers
Clematis paniculata – Sweet Autumn Clematis flowers

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.

Rose Mallow

Hibiscus 'Jazzberry Jam' -  Jazzberry Jam Rose Mallow
Hibiscus ‘Jazzberry Jam’ – Jazzberry Jam Rose Mallow

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.


Myth: Drought Tolerant Plants don’t need water

MYTH: Drought tolerant plants don’t need supplemental water

TRUTH: All plants need water!

Buddleia davidii 'White Profusion'  - White Profusion Butterfly  Bush
Buddleia davidii ‘White Profusion’ – White Profusion Butterfly Bush

Drought tolerant plants are those that, once established, will survive receiving the typical (or slightly less than typical) amount of rainfall in our area without the need for supplemental irrigation.

But to be clear, surviving isn’t necessarily garden tour ready! Prolonged periods without rain force the plant to conserve water in its most important tissues. With herbaceous plants, that’s the roots. For woody plants, this also includes the framework above the ground. Plants need a lot of water to produce new growth and keep their leaves hydrated. So, during times of drought many plants will stop growing all together and begin to shed leaves. Some plants will go completely dormant, and appear like they normally do in winter, with no sign of life at all above the ground.

In order to keep your plants looking their best, it’s a good idea to give them a deep soaking if it seems dryer than normal.

Keep in mind, plants that are considered drought tolerant generally have very extensive root systems, or a long taproot. When plants fresh from the nursery are put into the ground, they don’t have those roots yet to help them pull in moisture. We recommend keeping the area around new plants consistently moist (not soaking) for at least the first two weeks after planting. This give the plant time to send out new roots into the surrounding soil. After the first two weeks, monitor the soil in the bed. If there isn’t enough rain to keep the soil damp down a few inches, water weekly.


Clematis Pruning

Clematis 'Nelly Moser'
Clematis ‘Nelly Moser’

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.

Lavender

Lavandula 'Provence' - Provence French Lavender
Lavandula ‘Provence’ – Provence French Lavender

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.

If you want to grow lavender successfully, there are a few points to keep in mind.   Lavender is native to areas of the Mediterranean, Africa and Asia.   In order to keep lavender happy, try to provide conditions similar to its native habitat.  Well drained, gravelly soil, and full, hot sun are critical.  Drainage is the single most important factor, especially because we have such damp winters.  Lavender does not dying wet soil in winter.
The other important factor is pruning.  Do not prune lavender at all, if possible.  Simply dead head the spent stalks to above healthy foliage in late summer.  If plants do outgrow their space, or get leggy, shape them by removing about a third of the soft new growth from the current season.  Never prune them back into old wood.  Lavender resent this treatment, and may respond by giving up the ghost.
A few Common cultivars and their attributes:
  • 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″.

Catmint

Nepeta x fassenii 'Walker's Low'
Nepeta x fassenii ‘Walker’s Low’

A favorite of homeowners and landscapers alike, Nepeta x faassenii and its cultivars is a stellar plant for Nantucket. It forms a mound of pretty grey-green foliage early in the season, and is covered in blue flowers for well over a month in early summer. Cut it back in July, and you can expect the same show all over again before Labor Day.

Nepeta prefers full sun and well drained soil. It is extremely deer resistant and tolerant of salt, wind and drought. One island landscaper has taken to calling it the ‘The Welcome Plant’ since it is so friendly and easy care. There is a cultivar for nearly every situation. As long as you have at least a half day of sun, and some drainage, this plant will perform for you.

Common cultivars and their attributes are listed below:

  •   ‘Six Hills Giant’: At 3′ tall x 3 or more feet wide, this is the largest plant in this group. Great for covering a large area in a hurry. If not planted in full sun, this one can get floppy and splay open. Try shearing it back early in the season, to keep the plant stocky.
  •   ‘Walkers Low’: Don’t let its name confuse you, this is not a dwarf plant. It is named for a garden in England, were it was selected. 2007 Perennial Plant of the Year! 3′ wide and tall. Somewhat more compact than ‘Six Hills Giant’
  •   ‘Dropmore’: This one is considerably smaller than those listed above at 1.5′ tall and wide. A good option for smaller spots.
  •   ‘Blue Wonder’: Another good variety for smaller spaces. In my experience, ‘Blue Wonder’ is just slightly smaller than ‘Dropmore’, but the foliage is flatter and somewhat less grey.
  •  ‘Snowflake’: A small variety with clear white flowers. We don’t always stock it, but if your plan calls for white, try this cultivar. Not growing more than 15″ wide, it’s a good option for along a pathway, or a small white garden.
  •  ‘KitKat’: A true dwarf plant. This little one only grows to a foot or more tall and wide. Great to tuck in at the edge of the border.

Pruning Montauk Daisies

Many gardeners realize the benefits of pruning woody plants and trees. But perennials can really benefit from some pruning too! Montauk Daisies, Nipponanthemum nipponicum,  have a tendency to get huge and splay open late in the season, just as they come into flower. It’s nearly impossible to stake them or tie them and still make them look natural.

The solution to this problem is a little shearing early in the season. In May, cut back the growth by at least a third. Have no fear! They will rebound quickly, and the result will be a dense plant with shorter stems, capable of holding the flowers upright in Autumn. If you want a much smaller plant than previous seasons, consider one more pinching in June, before flower buds are set.

Before pinching
Before pinching in May
After pinching in May
After pinching 

Vines as Groundcovers

Clematis paniculata

When most gardeners think of vines, they picture them growing on tuteurs and trellises. But there is no need to pull out your hammer and nails every time you bring home a vine to plant!

There are plenty of vines that happily scramble along the ground, filling gaps and smothering weeds. Many of these will produce far more flowers grown horizontally. Clematis are a perfect example of this. Plant them at the front of the border and train them along areas often reserved for bedding plants, and they will reward you with a long show of flowers. Or let them flow around your shrubs, in waves of color. A Sweet Autumn Clematis in full flower is much like a wave cresting in the garden!

Vines can be a great solution to filling in shady areas, too. English ivy makes a fantastic green groundcover for deep shade. Why not use a Climbing Hydrangea along the ground? We’ve planted it below our welcome sign at the entry to the nursery. H. anomala petiolaris var. tilifolia has much smaller leaves than the species and will tightly hug the ground. Other options to consider are Schizophragma hydrangeoides, Akebia quinata or the ever popular Vinca minor.

We have a wide selection of vines in stock, why not consider one the next time you need to cover the ground in a hurry?