Author: Brad MacDonald

Inkberry, Ilex glabra, is a beautiful, rounded, evergreen shrub that grow 5 – 8′ tall.  It prefers full sun and evenly moist acidic soil, but does well in wet areas and light shade.  When properly pruned, inkberry can make a nice foundation plant or short hedge, but is best used in native screens and rain gardens, where it can be left to grow naturally with little intervention needed from the gardener.  Young plants are perfectly round, with leaves right to the ground.  As plants mature, however, the canopy tends to shade out the bottom portion of the plant and their lower branches can become bare and leggy.  Regular pruning is required to keep inkberry looking its’ best.

Most applications for inkberry call for a plant that is maintained at 3-4 feet.  Once they reach this size, they need to be pruned at least once a year to keep in bounds.  Shearing with hedge trimmers (when new growth has just hardened off in early summer) is the easiest way to prune rounded shrubs.  Although this approach takes the least amount of time, repeated cycles of shearing can make the surface of the plant very dense, shading out the lower branches.  I recommend doing a more thorough pruning procedure every other year to open up the plant.  More light penetration stimulates new growth at the base and keeps the plant healthier overall.  Should plants become overgrown and overly leggy, a renovation can be done during the dormant period in winter or early spring.  I’ve actually cut overgrown inkberry to the ground while dormant and had excellent results.

There are several objectives when doing regular pruning on inkberry:

• To remove dead or damaged branches
• To maintain the proper height and shape
• To keep the plant green from the ground up, (not leggy)

Understanding the growth pattern of these plants helps the gardener when making pruning decisions.  Growth in the upper portion of inkberry plants occurs in whorls.  A whorl is a ring of new stems that grow around a central, upright stem. There are many dormant buds between whorls on bare portions of the stems, even on the oldest woody stems.

On off years, when plants are not sheared, follow these guidelines:

1. Remove any dead or dying branches completely, where they meet healthy growth.
2. Pinch out most of the previous seasons’ growth just above a whorl to thin out the surface and keep the plant at the best height.
3. Most cuts are made in the previous season’s growth, but several cuts can also be made into older wood, to stimulate growth lower down.
4. As plants age, some of the oldest branches can be removed entirely at ground level in favor of younger, more vigorous growth.

There are several varieties of Inkberry available in the trade.  The most common are ‘Compacta’ ‘Densa’ and ‘Shamrock’.  Of the three, ‘Shamrock’ is the most highly praised by Dr. Michael Dirr in his extensive text book Manual of Woody Landscape Plants.  

Privet hedges are used all over the island as a beautiful way to border properties and break up large landscapes into smaller spaces.  In a lot of ways, privet is an ideal plant for tall hedges because it grows quickly and can be maintained at a relatively narrow width.  However, even well-maintained hedges slowly widen over the years, and established plantings will need a harder pruning every so often to stay healthy and in bounds.

Shearing hedges is a necessary part of maintenance, but this practice can cause problems in the long run.  When woody plants are repeatedly sheared, a dense layer of tiny twigs builds up on the outside, shading the interior stems and inhibiting dormant buds from sprouting.  As hedges age, dead wood can also accumulate in the center.  It’s not so much that it’s wrong to shear hedges; it’s more a matter of realizing that in order to keep a hedge healthy in the long run, renovation is required from time to time.  Removing the dense growth on the outside allows sunlight to fall on the dormant buds below, stimulating strong, healthy, new growth.  It also makes it much easier to saw out dead branches and scout for insect pests like scale and thrips that live directly on the bark.  This procedure is best done during the dormant season.

There are several ways to approach renovating a privet hedge.  Because privet grows rapidly, a declining hedge could be cut to within a few inches of the ground and allowed to completely regenerate.  If well irrigated and fertilized, one might expect 4-5 feet of growth in a single growing season.  This drastic approach won’t be acceptable in most situations.  I usually suggest that a hedge be renovated over 2 or three seasons, making deep cuts on one side per year.  Leaving one side un-pruned guarantees continued screening during the summer.  Although it can be nerve-wracking to make big cuts, be assured there are hundreds of dormant buds waiting just below the surface of each trunk and branch that will sprout once the sun shines upon them.

Be sure to use the proper tools for the job.  Branches narrower than ½” in diameter can be cut with regular hand pruners.  Branches up to 1” should be cut with sharp loppers.  Anything  wider than an inch should be cut with a hand-held pruning saw or chainsaw.

Consider following these steps:

1. Choose the side that will be worked on. Rake all the debris out from under that side.
2. Determine how much wood will be removed and set a string line along the ground as a guide for pruning. Make sure it is tight, and hovers above the ground without snagging on the lower branches of the hedge. 
3. A second line can be strung at chest-height as well, but it’s a challenge to get it in place before pruning. Tie the string line onto sturdy stakes that won’t pull in allowing the line to sag as you are working.   Prune around the line, so that hangs freely and doesn’t snag on the branches.
4. Start pruning on one end. Work from the ground up to as high as you can reach, establishing a vertical plane with the string lines as reference.  NOTE:  A properly pruned hedge has a narrow “A” shape; tighter at the top than it is at the bottom.  It is acceptable to maintain a 90 degree angle to the grade, but never allow the top portion of the hedge to splay out wider than the bottom.
5. From time to time stand back and scrutinize your work. When you are right next to the hedge, it’s hard to judge whether or not it’s straight.  It’s much easier to stand at the end that’s completd and look down the length of the privet with one eye closed.  Move back and forth slowly and you can see any spots that still poke out past the string line.
6. On taller hedges, you may need to make a second pass above your first to finish the job. Pole saws and pruners can be used.  There is even a chainsaw available that is on a long pole.  Personally, I much prefer using a sturdy ladder, or scaffolding made between two Little Giant ladders.  NEVER EXTEND A CONVENTIONAL CHAINSAW ABOVE MID-TORSO TO MAKE A CUT OR STRAIN TO TRIM A BRANCH JUST OUT OF REACH.  Always move your ladder to a comfortable working distance.  Don’t forget; the top should be narrower than the bottom.
7. I suggest pruning the top each time you do a renovation, even if you don’t want to reduce the overall height. This extra step allows maximum sun penetration over the upcoming season.
8. Once the major pruning operation is complete, make sure all dead wood is removed and take a good look at the bare wood remaining. Scale insects and thrips have become more of a problem on Privet over the last few years.  If large populations of any pest are found, consider applying a control.
9. Power-washing has become widely used as a means of destroying tiny insects that overwinter on woody plants. Although I haven’t tried this approach, I have heard good things about its’ efficacy.  Power-washing is best done while the plants are still dormant.  If you are considering it, do your research and complete the process before buds begin to break in spring.

We’re always on the lookout for plants that can solve problems for our customers.  We think spicebush, Lindera spp, might be one of those plants!  This wonderful native plant grows naturally from Maine to Ontario and Kansas and south to Florida and Texas.

This medium to large shrub, flowers in April on bare stems.  The yellow flowers remind me just a little bit of witchhazel, or winterhazel, but are smaller and held close to the twigs.  They are a good nectar source for insects waking up from their winter nap.  The mid-green, ovate, fragrant leaves turn yellow in the fall.  This plant is the sole food source for the spicebush swallowtail butterfly, and worthy of planting just to feed their caterpillars!  Similar to hollies, spicebush are dioecious, meaning they have separate male and female plants.  The males have somewhat showier flowers, but the females will produce red, elongated berries in the fall that feed migrating birds.

Spicebush is easy enough to grow in a wide range of soils and conditions.  Although they will have a denser habit in more sun, they perform well in part shade and do well in areas with moist soils.  Try planting it with arrowwood viburnum and Clethra in dappled sun.  Tall native perennials like Joe Pye weed and rose mallow would also make good companions.

Hydrangeas are funny ducks.  Sometimes their flowers are blue.  Sometimes they are pink.  Sometimes they are purple.  Sometimes they are red, sometimes they are fuchsia.  Sometimes they are white.  Sometimes they are a combination of all these colors.  We love the great variety of colors that these quintessentially Nantucket plants can bring to the garden, but many gardeners prefer one over another.  Traditionally, pastel blue has been the most sought after.  It seems simple enough.  Buy a blue hydrangea, plant it – done!  But with Hydrangeas it’s just not that simple.  So often, a gardener will buy a blue-flowered Hydrangea, plant it and find it bloom some other color the following year.  They puzzle over it.  They come in to the nursery saying, “I’m sure I planted ‘Nikko Blue’ it was perfect last year, now it’s pink!”  So what’s going on?

There are several factors that affect Hydrangea flower color.  The species of Hydrangea, the availability of aluminum in the soil, the time of year, and the amount of pigment in the flowers.

Not all Hydrangeas are able to change their flower color in the same way.  Mop head Hydrangeas, Hydrangea macrophylla (the ones with big, round, squishy flower heads), are very susceptible to aluminum. If mop head Hydrangeas absorb aluminum from the soil, the flowers will be blue or purple.  If there is no aluminum in the soil, or it is chemically unavailable to the plant, the flowers will be pink.  In addition, the soil must be acidic or the plant cannot absorb aluminum.  In soils 5.5 and higher on the ph scale the aluminum is “locked up” and cannot be absorbed.  Planted in soil that has a ph lower than 5.5, the aluminum is easily taken up by the plants causing blue flowers, even in plants that are meant to be pink.  So, you can easily have a blue ‘Forever Pink’ Hydrangea.  The reverse is also true.  A ‘Nikko Blue’ Hydrangea will be pink in alkaline soils.

Generally, Nantucket’s soils are lean and acidic, but not always!  If your blue Hydrangeas come out pink, aluminum sulfate can be added to the soil, changing them to blue.  It may take several applications, a few weeks apart, or even a whole growing season to get the color you are looking for.  Simply dilute the product in water and drench the soil around each plant, making sure to avoid the leaves.  Take care to follow the application rate on the package, as too much can burn the roots.  If your pink Hydrangea blooms blue, add lime to bring the ph closer to neutral.  Phosphorous also affects the availability of aluminum.  In order to keep the aluminum available, (and flowers blue) make sure to use a low-phosphorous fertilizer.  Choose a fertilizer with higher phosphorous to inhibit the aluminum, if you prefer pink.

The age of the flower and the time of year will also affect color.  Early in summer, most varieties will appear paler, almost bi-color, with most of the color showing at the edges of each floret.  As the flowers mature, the color generally becomes more even.  Later, as cooler nights arrive, the flowers enter their antique phase, and often appear reddish or deep purple.

The quality of the color is affected by the amount of pigment in the flower.  Each cultivar is different, but there are basically two groups as far as color saturation is concerned; Pastel and deeply saturated. In cultivars like ‘Glowing Embers’ there is a lot of pigment present in the flowers, allowing for very intense purples and/or pinky-reds. These plants will never be baby blue like ‘Endless Summer’.  No matter how much the soil chemistry is changed, there will always be a lot of pigment in these flowers, so they will always have deeply saturated color.  Conversely, cultivars similar to Endless Summer® can only produce pastel hues of blue, lilac and soft pink, there just isn’t enough pigment present in the flowers to allow for intense shades.

And then there is the whole question of white.  ‘Madame Emile Mouliere’, ‘Sister Theresa’ and Endless Summer® Blushing Bride, all purport to have white flowers.  Unfortunately, none of these stay clear white all season.  With afternoon shade, ‘Madame Emile Mouliere’ and ‘Sister Theresa’ will remain white for several weeks, but eventually take on a tinge of pink, or less often, blue.  ‘Blushing Bride’ usually takes on a pale pink hue, as well.  We are not aware of any way to keep the flowers white on these plants all season.

The take away:  If you want a blue Hydrangea, choose one that is bred to be blue, and plant it in acidic soil, using an acidifying fertilizer low in phosphorous.  If you’re shooting for pink, choose a variety bred to be pink, plant it in soil closer to neutral and use a balanced fertilizer, with higher amounts of phosphorous.  For white blooms, choose ‘Madame Emile Mouliere’, ‘Sister Theresa’ or ‘Blushing Bride’ be sure to give them afternoon shade.