Garden Notes

Thornless Honeylocust

September 23, 2011March 15, 2016, Posted by Brad MacDonald

Trees are one of the most impactful elements of any landscape. There are so many trees to chose from, it can be tough to select the right one for each application. Thornless Honeylocust is a great tree to plant in the lawn. It’s open branching and delicate leaves cast only dappled shade, so grass can be grown right up to the trunk, if desired.

In general, Gleditsia have a spreading irregular habit with ferny foliage. The leaves are green in summer and turn yellow in fall. Most cultivars have a short trunk and a wide spread. Some varieties will produce pendulous dark brown, twisting seed pods, that hang from the branches until late in the season, which can be a drawback. This tree is touted to be extremely tough and incredibly salt tolerant. However, during Irene, Gleditsia on the island suffered the same foliar damage as other deciduous trees.

There are several cultivars readily available in the trade, each with slightly different habits. Consider the following cultivars for your landscape:

Halka TM : Wide, symmetrical canopy. 40’t x 40’w in ideal conditions, closer to 30′ on the island. This variety may produce 8″ long pea-like seed pods that ripen to black and hang on the branches until late in the season.

Skyline R : Pyramidal form, with ascending branches. This variety maintains a central leader, making it appropriate for limbing up to create a higher canopy than most. 40’t x 35’w in ideal conditions, shorter on the island. Essentially podless variety.

Shademaster R: Excellent growth habit, upright ascending branching producing an irregular vase-shaped or rectangular form. Generally doesn’t produce seed pods. 45’t x 35′ w in ideal conditions, shorter on the island.

Salt and Wind Damage

September 1, 2011March 15, 2016, Posted by Brad MacDonald

After much hype and preparedness, Tropical Storm Irene blew across the island on Sunday with, thankfully, far less damage than forecasted. Now that any major issues resulting from the storm have been taken care of, and broken tree limbs have been cleared away, the flower garden might seem a little worse for wear! High wind, combined with salt spray and sand have left many plants with broken stems, and tattered leaves. Unfortunately, the battering and desiccating effect of the wind will continue to become more and more noticeable over the next few days.

Although the damage seems severe, especially in unprotected areas, remember that plants are resilient. It may look like someone has taken a blow torch to many of your prised plants today, but in time, nearly every plant will make a total recovery! So what can we do to help speed the process along and improve the overall look of the garden?

Give your plants a gentle shower with the hose to rinse off any salt that is still on the leaves.
It’s still hot out there! Be ready to add supplemental water in the areas of the garden that tend to get dry. Additional stress from drought will hamper growth.
Where time and patience allow, remove brown leaves from plants in the most visible areas of the garden.
Cut back, or re-stake tall perennials that have been blown over.
Visit the Nursery! A few well-placed additions to the garden can really help brighten things up, as we transition into the shoulder season.

Stewartia serrata salt and wind damaged foliage

Rose Mallow

August 18, 2011March 15, 2016, Posted by Brad MacDonald

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

July 28, 2011March 15, 2016, Posted by Brad MacDonald

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.

Pennisetum – Fountain Grass

July 28, 2011March 15, 2016, Posted by Brad MacDonald

Pennisetum orientale 'Karley Rose' - Karley Rose Oriental Fountain Grass — Pennisetum orientale ‘Karley Rose’ – Karley Rose Oriental Fountain Grass

Ornamental grasses continue to gain popularity. Even ten years ago, there were only a few varieties available, and even fewer gardeners who planted them. Today, there are hundreds of named cultivars, giving gardeners a wide variety of forms to chose from.

Fountain grasses are widely adaptable, rounded, clump-forming grasses. They are easy to grow, very deer resistant, and not bothered by insects. They look great as accents in containers, as mass plantings, or in mixed borders. The mounded shape is punctuated by bottle-brush shaped flowers from mid summer to fall.

Some notable varieties and their attributes are listed below:

•P. alopecuroides: The species form of hardy fountain grass. Tallest of the commonly available fountain grasses at 4′ tall. Flowers appear in late summer.
•P. alopecuroides ‘Hameln’: Referred to as a dwarf, this plant still reaches a solid 3′. Flowers appear in mid to late summer, before the species.
•P. alopecuroides ‘Little Bunny’: There are more and more truly dwarf fountain grasses becoming available. ‘Little Bunny’ originated as a seedling of ‘Hameln’, and is now widely available. It only grows to 18″. Flowers in Mid to late summer.
•P. alopecuroides ‘Maudry’: One of the latest blooming fountain grasses. Tops out around 2′. This cultivar has somewhat wide, deep green foliage. Nearly black flowers appear in October on short, stocky stems. Tends to self-sow.
•P. orientale ‘Karley Rose’: Early blooming variety with pink plumes. reaches 3′ tall and 2′ wide. Flowers begin appearing in July and continue through fall.
•P. setaceum ‘Rubrum’: Annual Red grass. Blades are entirely burgundy in color. 5′ tall x 3′ wide, with stunning plumes in late summer that arch above the foliage.

Wisteria: Summer Pruning

July 27, 2011March 15, 2016, Posted by Brad MacDonald

If you have ever seen a well trained Wisteria in full bloom in June, you may be tempted to add one to your garden. Keep in mind, Wisteria isn’t one of those plants you can put in the ground and forget about. Pruning in winter is very important, but there is pruning needed in summer, as well.

Before you get started, keep in mind your objectives:

To cover the support structure with well placed branches
To promote heavy flowering close to the main framework of branches.

Specific Summer Pruning Objectives:

To keep the vine in bounds
To increase sun penetration
To tie in new shoots to cover the support

SAFETY FIRST:

Working large vines that reach several stories overhead can be very dangerous. Follow these rules when pruning on a ladder:

Asses the support structure. Even pressure-treated wood and cedar will rot over time. Make sure the structure can support the vine and any weight you might put on it while pruning.
Nantucket is windy! Avoid working on a ladder on windy days.
Work with a partner. Someone on the ground to clean up and steady the ladder is very helpful.
Never stand on the top two rungs of a ladder
Work from below a pergola. Never climb up on top to prune. It is very easy to trip in the tangled vines or damage the laths.

With the objectives in mind, and safety as the top priority, begin to prune.

Cut back long tendrils to 6 inches. These vegetative shots will not flower and will shade the inner portions of the vine next to the support. In order to ensure good flower bud set, sun must penetrate into the Wisteria during the growing season.
Remove long side shoots at the base of the vine. This lateral growth will run along the ground and root, causing the wisteria to spread. *If the shoots arise from below the swelling where the Wisteria was grafted, it is even more important to remove them. It is nearly certain that these shoots will not possess the characteristics of the scion (the desirable grafted portion of the plant) and may be even more aggressive and difficult to control.
Tie strong shoots onto empty portions of the support. It is best to work systematically across the wisteria, pruning and tieing as you go. It helps to keep a center-pull ball of just twine in your pocket; this way, there is no need to climb up and down the ladder each time a vine needs to be tied.

Need a better visual? Check out our YOUTUBE video : www.youtube.com/watch?v=9BxUKPA4vx0&feature=youtu.be

Clematis Pruning

June 11, 2011March 15, 2016, Posted by Brad MacDonald

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

June 11, 2011March 15, 2016, Posted by Brad MacDonald

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

May 15, 2011March 15, 2016, Posted by Brad MacDonald

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

May 15, 2011March 15, 2016, Posted by Brad MacDonald

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.