Going the Distance with Ground Covers

In a tight spot and don’t know what to plant?  Try a ground cover!  Ground covers are a great way to fill in bare spots and add a unique touch to your landscape, while suppressing weeds.  “Ground covers” (or “Groundcovers”) are perennial ornamental plants that may be deciduous, evergreen, herbaceous, or woody.  Typically low-growing and planted en masse, ground covers often display attractive foliage and/or flowers. 

Photo: Ground cover Epimedium pinnatum subsp. colchicum used effectively; Cornell University, Ithaca

There are many reasons to plant ground covers.  Like any good ornamental plant, ground covers add beauty, novelty, and continuity to landscape designs.  Ground covers are also perfect for the sustainable garden.  By replacing turf grass with ground covers, you can reduce mowing, overall inputs, and excess maintenance, especially in areas where turf is difficult to maintain because it is too shady, too wet, or too sloped.  One of the main benefits of planting ground covers is that they can suppress weeds, reducing the need for herbicides or manual weeding.  Weed-suppressive ground covers grow fast and overwhelm competing vegetation.  Furthermore, ground covers can reduce soil erosion, foot traffic, and soil compaction. 

Planting recommendations for ground covers are not all that different from other ornamental plants.  First, be sure to prepare the planting bed properly by adding organic matter and adjusting for soil pH if needed according to soil test results.  After removing any offending weeds, plant the ground covers.  How far apart they should be planted is determined by their mature size.  For example, if a ground cover typically matures to 12-24 inches wide, you can space plants 12 inches apart from their centers.  After planting, add 2-3 inches of composted mulch (not fresh wood chips) to help maintain soil moisture.  Water the ground covers in and keep the soil moist until they are established.  You should plan on hand weeding around the ground covers during the first season.      

There are many unique ground covers to choose from, so don’t limit yourself to the old stand-bys like Pachysandra or English Ivy.  The Long Island Gold Medal Plant Program has awarded Gold Medal status to at least ten different and underutilized ground covers that perform admirably on Long Island.  One of these is ‘Fröhnleiten’ Barrenwort (Epimedium x perralchicum ‘Fröhnleiten’).  This herbaceous, evergreen ground cover also goes by the more appealing name Bishop’s Hat, which references the little yellow flowers which appear above the foliage in April.  This particular Barrenwort or Bishop’s Hat is a hybrid of two Epimedium species from the Middle East and North Africa but is hardy to zone 5 in the U.S.  ‘Fröhnleiten’ has attractive, glossy foliage that displays a reddish tinge around the edges of the new leaves and in winter.  It has a medium growth rate and will mature to a spread of 12-18 inches and a height of only 4-8 inches.  ‘Fröhnleiten’ Barrenwort grows best in light shade with even moisture, but it will also tolerate dense, heavy shade and dry soil where little else can grow.  ‘Fröhnleiten’ Barrenwort is perfect for shade or woodland gardens and planting beneath trees with dense canopies.  To make way for new foliage, cut the old foliage to the ground in late winter/early spring before new growth begins. 

Photo: ‘Fröhnleiten’ Barrenwort (Epimedium x perralchicum ‘Fröhnleiten’) in early spring; Atlantic Nurseries, Dix Hills

Another award-winning ground cover is Creeping Phlox (Phlox stolonifera).  Creeping Phlox is much more subdued and less showy than the ubiquitous Moss Phlox (Phlox subulata), which is also sometimes called Creeping Phlox.  P. stolonifera is an herbaceous, deciduous flowering ground cover that is native to the Eastern U.S., where it grows wild in the woodlands and along the streambanks of the Appalachians.  It prefers to grow in moist soil, rich in organic matter, in the partial shade.  It grows 12 inches wide and only 3 inches tall.  Its foliage is non-descript, but it is a stunner in the early spring when deep lavender flowers appear on stems rising 6 inches above the foliage.  Creeping Phlox is truly a head-turner with its delicate and ephemeral beauty.       

Photo: Creeping Phlox (Phlox stolonifera) in bloom; Long Island Horticultural Research & Extension Center, Riverhead

So the next time you are scratching your head wondering what to plant in an empty spot in your garden, consider a ground cover!  Both attractive and functional, ground covers are a great addition to any landscape.

Other Gold Medal Ground Covers -

Carex morrowii ‘Ice Dance’- Japanese Sedge

Ceratostigma plumbaginoides - Plumbago

Geranium x cantabrigiense ‘Biokovo’ - Hardy Geranium

Microbiota decussata - Russian Arborvitae

Sarcococca hookeriana var. humilis - Dwarf Sweetbox

Sedum spurium ‘John Creech’ - Two Row Stonecrop

Stachys ‘Helene von Stein’ - Helene von Stein Lamb’s Ears

Waldsteinia ternata - Siberian Barren-strawberry

For more info. visit:

http://ccesuffolk.org/the-long-island-gold-medal-plant-program/

How to Hire a Professional

When it comes to gardening, I like to do everything myself.  I enjoy both the process and the finished results of planting, weeding, pruning, thinning, and everything else involved in gardening.  Being outside, absorbed in my work, hours can pass without me realizing.  I can either zone-out or think about things that occurred during the day – either way, it’s my time.  Despite often being covered in sweat, dirt, and mosquito bites, I enjoy gardening because it helps me feel alive.  Using all my senses while immersed in the garden, feels so much more real than staring at a computer screen, which I admittedly do for far too long each day, like so many other people today.  While working in the garden, I’ll notice things that I didn’t notice before, and I’ll start to feel connected to something greater.  And before I know it, the light will be getting dimmer, and I’ll start making deals with the sun, pleading, “Just please let me finish pruning this hedge before it gets too dark and I have to go inside!” 

For all the enjoyment and satisfaction I get out of gardening, there are other, far less glorious reasons why I like to do everything myself.  For starters, I have certain ways of doing things and can be quite particular.  It’s not full-blown O.C.D., but it might be close.  When I was 13 and had to mow my family’s lawn every week, I ensured that all the lines the mower made in the grass were perfectly parallel.  Once I had finished mowing, I would walk across the street and assess the grass line situation and make sure that I had done a perfect job.  I’m sure the neighbors never figured out what I was doing – they were simply shocked at the sight of a 13 year old girl behind a lawn mower. 

Which brings me to the last reason why I like to do everything myself in the garden; I don’t like people telling me I can’t.  When cars would slow down to stare at me mowing my family’s lawn, or neighbors would drop off the number of their landscaper unrequested, I got the keen sense that society was telling me I couldn’t.  But to me, it was an extra $10 or $15 (depending on if I edged or not) and to my parents it was a sweet deal, so I kept on mowing.  But there are times in everyone’s life when they realize that they really can’t do something and need to suck up their pride and hire a professional.  Below are the ways you can hire a professional landscaper, arborist, or certified applicator.  By following these suggestions, you’ll be the most likely to get both professional service and the results you want. 

Landscaper
Landscaping is really divided into three main categories – landscape design (a plan for your garden), landscape installation (obtaining and planting plants for your garden), and landscape maintenance (maintaining your lawn and/or shrubs). 

Photo: A landscape designer can help you select ornamental plants that are best suited for your site and design a beautiful garden out of them. Environmentals, Cutchogue

Some companies are specialized in only one of these categories, while others will be able to do all three, so you have to be clear as to what you want and what the company can provide.  When hiring a landscaper, make sure that he or she is a member of a local professional organization.  Both the Nassau Suffolk Landscape Gardeners Association (NSLGA) and the Long Island Nursery & Landscape Association (LINLA) offer numerous and high-quality educational programs and training sessions so that members can keep abreast of local trends and new regulations and maintain their credentials.  Furthermore, landscapers are required to have insurance and numerous licenses which the professional organizations help their members obtain and keep.  For fully licensed and insured landscape professionals working in your area, call the NSLGA office at 631-665-2250, or search the Nursery & Landscape Association’s member database (Region 1) at: http://www.nysnla.com/index.php?option=com_civicrm&view=Profiles&layout=search&Itemid=144

Arborist

An arborist will be able to take care of your trees and shrubs.  Arboriculture is really divided into two main categories – general tree care which includes pruning and tree removal, and plant health care, which includes pest, soil, and root zone management.  

Photo: Properly managing the root zone of trees has recently been shown to have a dramatic impact on tree health, Planting Fields Arboretum, Oyster Bay

Like landscaping, some arboriculture companies are specialized in only one of these categories, while others will be able to do both.  When hiring an arborist, make sure that he or she is a member of a professional organization.  Both the Long Island Arboriculture Association (LIAA) and the International Society of Arboriculture (ISA) offer numerous and high-quality educational programs and training sessions.  For arborists working in your area, view the LIAA membership list at http://www.longislandarborists.org/membership_list.html   or you can search the ISA website for an
ISA certified arborist in your area at http://www.isa-arbor.org/faca/findarborist.aspx

Photo: A certified arborist will be able to safely provide professional tree care services

Certified Applicator

Any professional who treats pests must be a certified pesticide applicator.  This is true even if organic means are utilized.  Individuals who are certified applicators are often landscapers, arborists, exterminators, farmers, and nursery growers.  If you have a pest infestation on your trees or shrubs, or in your lawn or house, you’ll have to hire a certified applicator if you are using a professional.  A certified applicator will also be able to help you treat weeds and invasive plants.  All New York State certified applicators are listed alphabetically on the Department of Environmental Conservation’s website http://www.dec.ny.gov/docs/materials_minerals_pdf/appweb.pdf  Check this list to ensure that the individual is currently a certified pesticide applicator.  Many certified applicators are also members of the organization, Professional Certified Applicators of Long Island which offers educational programs.  Call the office at 631-744-0634 to find a member in your area.

By hiring a qualified professional, you can save both time and frustration, knowing that your garden is being cared for properly.  At least for now, I no longer worry about the lines in my lawn, and entrust the mowing to my professional landscape maintenance service.  And if any major tree pruning needs to be done, I’ll be sure to call a professional arborist!

Plants for Long Island’s Shores

No matter where you are on Long Island the open sea is only 20 minutes away or less.  From the Atlantic Ocean to the Long Island Sound, the Peconic Bay to the Great South Bay, Long Island is surrounded by deep blue waters.  As Long Islanders, we are truly blessed to be able to have our long summer days filled with sand, salt spray, and sunshine.  Whether we are soaking up the rays with friends on a packed field at Jones Beach, or quietly dipping our toes into the calm waters of the Sound, Long Island’s shorelines have something for everyone to enjoy.

Photo: Homes along the Great South Bay, Patchogue

Although the sea may be renewing and refreshing for the human soul, it is a tough and inhospitable place for plants.  Those plants that do grow along the coastline must deal with extremely challenging growing conditions, including high winds and salt. 

Photo: Pines shaped by the elements, Davis Park, Fire Island

Wind increases plant transpiration and water loss and blows abrasive sand onto plants.  Wind can also carry saltwater droplets which may then be deposited on leaf surfaces.  Both aerosol and soil salts can have negative consequences for plants.  Because of its lower osmotic potential, saltwater will draw moisture out of plant roots and leaves, causing an injured plant to display drought-like symptoms including foliar browning and leaf drop.  Tender new leaves of plants within 1,000 feet of the shoreline are the most susceptible to salt spray injury.  Sandy soils with few nutrients and little water-holding ability compound the problem, making the seashore a very harsh growing environment.

Few plants are adapted to such tough conditions, but if you choose wisely, you can still have a lush and beautiful beachfront garden.  Seaside plants must be able to thrive in intense sun and must be salt and drought-tolerant.  Seaside plants must also be able to grow in very well-drained sandy soil with few nutrients and little organic matter.  Plants native to coastlines have naturally evolved under harsh conditions and most often fill these requirements.  Specific adaptations like thick, leathery leaves which help protect from salt spray injury, enable adapted plants to grow along the shoreline.  When planning your beachfront garden, keep in mind that salt-tolerance of plants varies along a continuum, and always place the most salt-tolerant plants closest to shore.  These plants will be the most likely to survive and will help buffer your other plants from wind and salt spray.   

Two underutilized salt-tolerant shrubs that are perfect for Long Island seaside gardens are Virginia Rose (Rosa virginiana) and Eastern Baccharis (Baccharis halimifolia).  Virginia Rose is a native rose found from Newfoundland to Virginia and west to Missouri.  In late spring and early summer, it is covered in fragrant, single pink blossoms that have soft yellow centers.  Ornamental rose hips follow the flowers and persist through the winter.  Virginia Rose is salt-tolerant and grows best in full sun in sandy, well-drained soil.  It grows to 4-6 feet tall and wide.  Because it can sucker and spread quickly, Virginia Rose is ideal for covering large areas of coastal gardens, forming beautiful drifts of flowers.  Also, Virginia Rose does not need numerous applications of pesticides because it is highly resistant to the common diseases that plague other roses, such as rust and black spot.  

Photo:  Native Virginia Rose (Rosa virginiana) is attractive to pollinators.

Eastern Baccharis is a medium to large, deciduous shrub that is native to the East Coast from Massachusetts to Florida, and west to Texas.  Reaching a mature height of 5-12 feet, Eastern Baccharis has a dense, rounded habit.  Although its deep green to gray-green, uniquely-shaped leaves are present throughout the growing season, its main ornamental feature does not become apparent until fall when the cottony fruits appear and transform the plant into a billowly cloud.  Eastern Baccharis grows best in full sun and is highly salt-tolerant.  It is adaptable to many different soil types including pure sand.

Photo: Eastern Baccharis (Baccharis halimifolia) in October.

Photo: Eastern Baccharis along the shoreline of Heckscher State Park, East Islip.

Both Virginia Rose and Eastern Baccharis are native to Long Island’s maritime shrubland habitats which naturally occur behind stabilized back dunes.  Although some distance from the open beach and dunegrass, maritime shrublands are still subject to salt spray and offshore winds.  Just because your home is along the shore doesn’t mean that you can’t have a beautiful garden.  Wisely choosing salt-tolerant plants like Virginia Rose and Eastern Baccharis enable you to create your own seaside garden escape!  For further information, read Seascape Gardening: From New England to the Carolinas by Anne Halpin, Storey Publishing, 2006.  You may even recognize some photos from Long Island!

 

Happy Hydrangeas, Part 2: Blue or Pink?

One of the most curious things about Bigleaf Hydrangeas (Hydrangea macrophylla) is their chameleon-like ability to change color.  That striking pink-flowered hydrangea you just planted from your local garden center may have blue flowers by the time next year rolls around.  Likewise, that stunning blue-flowered hydrangea you just transplanted from your mother’s house may have pink flowers next growing season.  But how can this be?!  What makes a hydrangea change color, and how can you be sure that it will stay a certain color?

Photo: Bigleaf Hydrangeas (H. macrophylla) come in a rainbow of pinks and blues

The answer to this perplexing plant phenomenon has to do with aluminum in the soil.  Aluminum is the most abundant metal in the Earth’s crust, but it is toxic to almost all plants.  There are very few plants that can actually accumulate aluminum internally without any ill effects.  One of these rare aluminum-tolerant plants is Bigleaf Hydrangea.  Hydrangea uses organic acids to detoxify aluminum, forming aluminum-citrate.  While inside the plant, aluminum also reacts with the plant pigment anthocyanin, producing a blue hue in the flowers.  As the concentration of aluminum in a hydrangea increases, the intensity of the blue color also increases. 

Thankfully for all the non-aluminum-tolerant plants, this metal cannot typically be absorbed by plant roots in its normal form.  Only when the soil is very acidic and the pH drops below 5.5, does aluminum change and become the soluble ion Al3+ which can be absorbed by plant roots.  So even if aluminum is present in the soil (which it almost always is), it may not be available to your hydrangea because the soil is not acidic enough. 

If you want to change the color of a Hydrangea that is planted outside, focus on adjusting the soil pH.  Always take a soil pH test before doing anything.  Based upon the results of your pH test, you can add elemental sulfur to the soil which will slowly lower the pH over time, eventually resulting in bluer hydrangeas.  Or you can add lime to the soil which will more quickly increase the pH, resulting in pinker hydrangeas.  Still, changes in soil pH typically take several months, so patience is key.  Also, be aware that soils near concrete walkways and house foundations as well as turf areas that have been heavily limed will be more alkaline, and work better for growing pink hydrangeas.   

Photo: Pink flowered hydrangeas show their colors in more alkaline or basic soils - those with a higher soil pH

On the other hand, if you are growing a hydrangea in a container and have used potting mix rather than mineral soil, there is a good chance that aluminum is missing.  If you’re looking to grow a potted hydrangea with bright blue flowers, you might need to add some aluminum sulfate.  This specialty soil amendment supplies aluminum while lowering the pH.   The tricky part though, is knowing how much aluminum sulfate to apply.  At too high aluminum concentrations, even aluminum-tolerant Hydrangea can be dwarfed and killed.  Even the great plant-God, Michael Dirr has admitted to killing Hydrangeas with too much aluminum sulfate.  For potting mix that has no soil in it (and therefore no existing aluminum), Dirr recommends that 0.75 – 1.5 ounces (21 – 42 grams) of aluminum sulfate be applied to the surface of a 3 gallon container.  Multiple applications at this rate may be needed if the pH remains higher than 5.6.  Make sure to read all label directions carefully and follow application rates carefully!  Some hydrangea growers will apply aluminum sulfate at the end of the season in August or September, and then again during the forcing stage the following spring.  It is important to water thoroughly after application to ensure movement into the root zone and to not apply when the potting mix is dry. 

Photo: Before adding any soil amendments, be sure to always take a soil test.

Lastly, the type of fertilizer you use can also affect hydrangea flower color.  Nitrate nitrogen fertilizers increase the pH, and ammonium nitrogen fertilizers lower the pH.  High levels of phosphorus can decrease the uptake of aluminum, while high levels of potassium can increase the uptake of aluminum.

In summary, if you want blue or pink Hydrangeas:

·         Blue:  high Al, pH 5.0 – 5.5, very low P, high K, and moderate ammonium N

·         Pink:  low Al, pH 6.0 – 6.5, high P, low K, and high nitrate N

Hopefully that clears up some of the mystery behind Hydrangea coloring, a topic that is almost as confusing as Hydrangea pruning!  If you’d like to learn more about hydrangeas, a great resource is Hydrangeas for American Gardens by Michael Dirr from 2004, published by Timber Press.

Happy Hydrangeas, Part 1: Pruning

Warm weather is finally here and the excitement and relaxation of summer is just around the corner.  One of the simple pleasures I look forward to every summer is the blooming of my mophead hydrangeas.  I have two ‘Nikko Blue’s stuffed and crammed into my very small, overcrowded, front garden.  Their thick stems and toothed leaves are already claiming the walkway, and I have to be careful not to knock them as I make the short walk from door to driveway.  But they are totally worthy of such prized garden space.  Already, I can see the tiny green flower buds forming in the leaf axils, which in the coming six weeks will yield heaping mounds of sky blue flowers. 

Photo: Bigleaf Hydrangea with Day Lilies in my summer garden, Commack

If you’re a hydrangea aficionado (like so many gardeners are these days), I’m sure you also feel excitement when you see their tiny green flower buds forming.  Or, frustration when you don’t.  If you have a mass of hydrangea leaves and no flowers, you might be wondering, what the heck did I do wrong THIS time?!  Most likely, the answer is that they were pruned incorrectly (or that the cold killed the tops of them.)

Let me start by saying that hydrangeas are tricky in both pruning and cultural requirements.  There have been a handful of times when landscape professionals have called me up asking what the heck they did wrong THIS time to Mrs. Smith’s hydrangeas.  The trickiness of pruning hydrangeas begins with the fact that there are so many different types of hydrangeas.  You need to know which is which, sometimes down to the cultivar level, in order to prune them correctly… 

The four main species of shrub hydrangeas are Smooth Hydrangea (Hydrangea arborescens), Panicle Hydrangea (H. paniculata), Oakleaf Hydrangea (H. quercifolia), and Bigleaf Hydrangea (H. macrophylla).  Smooth Hydrangea is actually native to New York, and grows along forested streambanks in its natural habitat.  Common cultivars include ‘Annabelle’ and Incrediball™.   

Photo: White Dome® Smooth Hydrangea - H. arbroescens, Ithaca 

Panicle Hydrangea can be seen on many old homesteads, flowering in late summer.  The white flowers fade to a dull mauve as the season wanes.  Common cultivars include the old standby PeeGee (‘Grandiflora’), and the newer, quite popular Limelight® and ‘Tardiva.’  Oakleaf Hydrangea, in addition to their big, bright white flower panicles, has oak leaf-shaped leaves which turn a lovely burgundy in the fall.  Cultivars include ‘Alice’ and Snow Queen ™. 

Photo: Oakleaf Hydrangea - H. quercifolia, Old Westbury Gardens

Bigleaf Hydrangea is by far the most popular hydrangea today.  The innumerable cultivars of H. macrophylla are divided into two groups – mopheads and lacecaps.  Bigleaf Hydrangea does admirably on Long Island.  It is fairly salt-tolerant and can be planted in sandy, acidic soil.  It does needs plenty of water though, and some cultivars are not quite cold-hardy during severe winters.

While removing dead flowerheads and dead branches can be done anytime of the year to any species of hydrangea, removal of live branches should be done only at certain times if you want your hydrangea to flower.  Both Smooth Hydrangea and Panicle Hydrangea bloom on the current season’s growth.  This means that the optimal time to prune live branches without impacting flower production is late winter/ early spring before new growth starts.  On the other hand, both Oakleaf Hydrangea and Bigleaf Hydrangea bloom on last season’s wood, which means that flower buds have already been formed in the fall to flower the following spring.  Because of this, pruning in late winter/ early spring (the optimal pruning time for many plants) would remove those existing flower buds.  New ones would not be formed.  Therefore, for Oakleaf and Bigleaf Hydrangeas, pruning live branches should only be done after flowering in August or by mid-September at the very latest.

Now that I’ve made that perfectly clear, let me backtrack and say that there’s one exception.  (There’s always an exception in horticulture!)  There are a few cultivars of Bigleaf Hydrangea which flower on both old and new wood.  This means that if you accidentally prune off the flower buds in late winter/ early spring, no big deal - new ones will form on the new growth.  These reblooming hydrangeas are “remontant,” meaning that they flower on both old and new wood.  Most outstanding is the Endless Summer® Collection by Bailey Nurseries, Inc. of St. Paul, Minnesota. 

Photo: Endless Summer® Mophead Hydrangea - H. macrophylla, Hicks Nurseries

World-renowned plantsman, horticulture ‘God,’ and living plant legand, Michael Dirr, helped discover the original Endless Summer® plant, and led tests of it in his University of Georgia lab, which confirmed its remarkable reblooming ability.  In 2004, Endless Summer®, the first tested, truly reliable remontant Bigleaf Hydrangea, exploded on the market.  Now seven years later, a couple other reblooming hydrangeas have popped up, and the hydrangea-craze seems to be at an all-time high.  These reblooming hydrangeas have simplified the pruning requirements for Bigleaf Hydrangeas.  Now, if only we could all figure out how to keep our hydrangeas blue!  To be continued!