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The Hills Are Alive! Mountain-laurel Is Worth the Effort

Considered by many to be one of the most beautiful flowering evergreen shrubs or small trees in North America, mountain-laurel’s native range extends from New England to the Florida panhandle and west to Indiana. It’s widely distributed in the mountains with smaller natural populations in the Piedmont and Coastal Plain.

The springtime flowers, each 3/4 to 1 in. wide, are massed in 4-6 inch-wide inflorescences that range from white to pink and crimson and purple. The evergreen foliage is used in winter holiday decorations. Over time it can reach a height and width of 12 to 15 ft. with a gnarled, picturesque trunk.  The 2-5 inch long leaves emerge bronze and mature to lustrous dark green.

Unfortunately, mountain laurel is one of the more difficult plants to propagate in the nursery trade. Over the years an assortment of approaches have been proposed by nursery professionals and researchers. No consensus had been reached. However, the experts agree that some cultivars root more easily than others

Kalmia latifolia Bullseye 05_04_2015 SCBG

from cuttings. Cultivars that are easiest to root include ‘Bullseye’ (pictured), ‘Carousel,’ ‘Nipmuck,’ ‘Olympic Fire,’ ‘Pink Charm,’ ‘Pink Surprise,’ ‘Quinnipiac,’ and ‘Sharon Rose.’

Mountain-laurel tends to be challenging to grow in the landscape as well. While it can be found growing luxuriously in the wild without any human intervention, it doesn’t exhibit an identical performance in the landscape. In fact, many experienced gardeners have questioned their hard-earned skills when they watch their nursery-propagated mountain laurels turn brown and dry within the first few years after planting. My longtime friend, Dick Bir, recommends in his Growing & Propagating Showy Native Woody Plants (UNC Press, Chapel Hill) book adding a few inches of pine bark into the mineral soil before planting. He also recommends a location in light shade that receives a few hours of sun a day.  It should be an extremely well-drained, acid location.

Avoid the urge to apply copious amounts of fertilizer. Unlike the tomatoes, peppers, and okra in your vegetable garden, mountain-laurel is a light feeder that can be harmed with excessive fertilizer applications.

Mountain-laurel or calico-bush may be a tad persnickety in the landscape, but the extravagant flowers are worth your time and effort.

Bob Polomski  © 2017

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Got daylilies?

Although daylily flowers last only a day (the genus Hemerocallis comes from the Greek hemera which means “day” and kallos means beauty), these no-fuss no-muss herbaceous perennials are the workhorses of the landscape. In fact, even the Department of Transportation uses daylilies. This summer as travelers cross the highways and byways of the Carolinas, look for sweeping beds of daylilies in medians and along bridge embankments. When the DOT grows daylilies, you know it’s a tough and attractive plant.

Daylilies provide a rainbow of flower colors that range from near-whites, pastels,IMG_0832 yellows, oranges, pinks, vivid reds, crimson, purple, nearly true-blue, and fabulous blends. Their clumps of arching sword-shaped leaves may be evergreen, semi-evergreen, or deciduous and vary in height from dwarf (under 6 in.) to medium (about 2 ft.) and tall (3 ft. and over). Their bloom season begins in mid-Spring and lasts into late summer.

Reblooming daylilies flower more than one time during a single season; some of them bloom early-May or June–and then repeat in the fall. Others have a succession of bloom periods, one shortly after another for several months. Reblooming types include the 3 ft. tall Starburst series, which come in a variety of colors, as well as the 2 ft. high ‘Black-eyed Stella’ (yellow with red eye), bright yellow ‘Happy Returns’ and ‘Stella de Oro’, and the red ‘Pardon Me.’Daylily6_19_05[1]

With over 58,000 cultivars of dayliles, you’re bound to find one that you like. There are selections with semidouble and double flowers. The tetraploid types have unusually heavy-textured petals. (Visit The American Hemerocallis Society www.daylilies.org/ for a gardener-to-gardener discussion of diploids vs. polyploids.)

Daylilies need about 6 hours of sunlight each day, although they will tolerate light shade but will produce fewer flowers. They spread from suckers to form a dense mat, so expect to divide them every 3 to 6 years.

If you have a drab-looking space that needs some sprucing up this summer, choose low maintenance daylilies for their versatility and their gorgeous flowers.

Bob Polomski  © 2017

Growing citrus outdoors

Raising citrus in USDA cold hardiness zone 8a–outside of the traditional citrus-growing regions–is made difficult both by minimum winter temperatures, and by fluctuations in temperature that interfere with citrus achieving maximum winter hardiness. However, a four-year evaluation of citrus cultivars in Savannah, Georgia when the winter temperatures dipped to between 13 and 18 degrees F. suggests several possibilities. (See “Field Evaluation of Cold Hardy Citrus in Coastal Georgia” by M. Rieger et al., HortTechnology Vol 13, No.3, 2003).  Among the survivors were  the mandarins ‘Owari’ (grafted on sour orange rootstock) and ‘Changsha’  (own-rooted),  a citrangequat ‘Mr. Johns Longevity’ (both own-rooted and grafted on ‘Carrizo’ citrange rootstock), and the orangequat ‘Nippon’ . These plants experienced some defoliation and minor shoot dieback, but they fruited consistently on an annual basis.Citrus 10_24_2013 BP

To improve any citrus plants chance of survival, plant in a well-drained location in full sun, preferably at the top of a southfacing slope with protection from prevailing winter winds.  Planting in raised beds will improve drainage and will encourage the soil to warm up more quickly.

Young trees are less cold tolerant than mature trees, so care during first three growing seasons after planting is critical for their long term survival.

citrus

Keep the tree well-watered and avoid fertilizing between Aug 1 and Feb. 15 to avoid encouraging growth that can be injured by frosts. For more information about growing citrus and other tender plants visit the Southeastern Palm and Exotic Plant Society web site. Also, see Hardy Citrus for the Southeast by Tom McClendon.  The following chart prepared by Tom McClendon appeared in the Southeastern Palms newletter (Spring 2011, Vol 19-1).  Reprinted with permission.

Variety USDA Hardiness Zone Evergreen Taste
Morton citrange 7B Mostly Sour
Benton citrange 7B Mostly Sour
Trifoliate citrangequat 7B Nearly Sour
Thomasville citrangequat 7B/8A Fully Semi-sweet
Dunstan citrumelo 7B/8A Nearly Sweet
C. taiwanica 7B/8A Fully Sour
Ichang lemon 8A Fully Sour
Yuzu 8A Fully Sour
Taichang 8A Fully Sweet/Sour
Yuzuquat 8A Fully Sour

Bob Polomski  © 2017

False indigo for Mom

If you panicked and just remembered that today is Mother’s Day, you probably bought a florist hydrangea with its bowling ball-sized pink or blue flowers and colorful foil wrapping. Fine, but doesn’t Mom deserve more than this impulse purchase? Next year, consider giving her a false or wild indigo (Baptisia [pronounced bap-TIZZ-ee-uh]). For years I’ve written and spoken about this easy-to-grow and enjoy herbaceous perennial that blooms reliably every year during Mother’s Day.
False indigo  is a native American perennial comprised of 15 species and sbaptisia-australis_purpleeveral naturally occurring hybrids that offer a range of flower and leaf colors. Many years ago native Americans and early settlers relied on false indigo to create colorful yellow, brown, and green dyes. In fact, the scientific name is derived from the Greek word, bapto, which means “to dip” or “immerse.” Indigo, a highly sought after and rare color among natural dyes, was actually extracted from the leaves and stems of the yellow-flowered Baptisia tinctoria.
For years false indigo wallowed in obscurity, which surprised me. Depending on the species and cultivar, false indigo flowers come in deep blue to yellow (B. tinctoria) or creamy-white (B. bracteata).  At this time of year tall spikes of pealike flowers rise above the three-lobed leaves to provide a three- to four-week long display. Eventually they give rise to black seed pods that remain for most of the summer. Some folks consider the ripe, charcoal-black seed pods as having ornamental interest. I like the noise the pods make when I shake them, which reminds me of a baby rattle. When planted in a well-drained location in full sun, expect false indigo to reach a height and spread of 3 to 4 feet by the end of the season.
Besides its leaves and flowers, I love Baptisia for its drought tolerance and sheer ruggedness.  It’s a great “starter” plant for new gardeners because false indigo quickly recovers from any mistakes. For example, years ago my six-year-old son harvested all of the new shoots as they poked through its mulch blanket in mid-April. He thought that if the shoots looked like asparagus, they must be asparagus. I was mortified when I saw him carrying an armful of wild indigo shoots in his arms and a beaming smile on his face. (I was also floored by my son’s gustatory interest in asparagus.) No problem. The wild indigo responded by producing more asaparaguslike shoots that bloomed magnificently.
An added bonus to growing false indigo are the flowers that provide sustenance to bumblebees and leaves that feed the larvae of a variety of butterflies that include wild indigo duskywing, frosted elfin, eastern tailed-blue, silver-spotted skipper, and sulphurs.
In 2010 false indigo was recognized as a rising star when blue false indigo () was selected as the Perennial Plant of the Year™ by the Perennial Plant Association. Although its specific epithet, australis, is Latin for “southern,” it happens to be one of the most adaptable of native species growing across a range of USDA cold hardiness zones.
As a result of its growing popularity, from 2012 to 2015 the Mt. Cuba Center in Hockessin, Delaware conducted a trial of 46 different selections from 11 different Baptisia species and cultivars.  For the mid-Atlantic region (USDA hardiness zone 7a/7b) the Mt. Cuba Center recommended these top 10 cultivars for their garden worthiness: ‘Screamin’ Yellow,’ ‘Lemon Meringue,’ ‘Ivory Towers,’ ‘Blue Towers,’ ‘Purple Smoke,’ ‘Cherries Jubilee,’ ‘Sunny Morning,’ ‘Blueberry Sundae,’ ‘Dutch Chocolate,’ and ‘Crème de Menthe.’
It’s not too late to get Mom a false indigo and a nice card with these words: “Mom, you remind me of false indigo. You’re tough, durable, and beautiful.”
Well, you may not want to use those exact words.  But you can’t go wrong by calling Mom and false indigo “beautiful.” Happy Mother’s Day!
Bob Polomski  © 2017

Red buckeye is a feast for gardeners and wildlife

Although red buckeye (Aesculus pavia) lacks the refined and symmetrical stature of commercially successful small ornamental trees, it makes up for it with an impressive show of 6- to 10-inch long salmon- to cherry-red floweraesculus pavia_R Polomski spikes borne at the ends of its branches. These hummingbird magnets emerge in April and coincide with the spring migration of ruby-throated hummingbirds. The nectar also fortifies other pollinators including eastern tiger swallowtail butterflies, bumblebees, and carpenter bees.

In nature this large shrub to small tree (10 to 20 ft.) grows wild in floodplains and swamp forests throughout the southeast; however, I’ve seen it successfully cultivated en masse in woodland gardens, as accent or specimen plants in landscapes, and in downtown city parks

Once the flowers have faded I enjoy the dark green palmately compound leaves and smooth gray bark. Later in the season potato-shaped husks that arose from the flowers mature and split open in September and October to reveal 1 to 3 shiny brown nut-like seeds. The seeds are poisonous and avoided by most wildlife, but relished by squirrels.

Red buckeye checks out and goes dormant by September with no colorful fanfare. However, when provided with moist, partially shaded conditions, the leaves will turn yellow.

I accept the early departure of red buckeye as it disappears in my landscape. Its leafless branches receive quizzical looks from friends and passersby who typically ask: “Is it dead?” Despite its forlorn look in the fall and winter months, red buckeye will always have a place in my garden. Its flowers sustain my spirit and they nourish the bodies of well-traveled, winged pollinators.

Bob Polomski  © 2017

The rise and fall of the Bradford pear

Once upon a time the Bradford pear (Pyrus calleryana ‘Bradford’) was the darling of the nursery industry. Since its debut on the cover of American Nurseryman magazine on April 15, 1963, Bradford pear’s popularity soared as a street-tough tree that offered beauty and durability. In early spring Bradford pear trees erupted into bloom, these giant ovate snowballs of bright white flowers that were best admired from a distance because of their rotting fish aroma. The flowers, favored by honeybees, bumblebees and other pollinators oblivious to the stench, gave rise to leathery, dark glossy green leaves that “present[ed] a pleasing picture, particularly as they stir in the breeze and their wavy edges catch and reflect the sun’s rays,”  according to the authors of the 1963 American Nurseryman article “Bradford ornamental pear—a promising shade tree.” In the fall the longlasting leaves exploded into shades of orange, red, and purple. The beauty of Bradford pear was matched by its unparalleled toughness: tolerance to drought, pollution, and pests, notably to fire blight, a devastating bacterial disease that injures and kills edible pears.

Bradford pear appeared to be the perfect ornamental street tree, but like kryptonite and Superman, Bradford pear’s Achille’s heel was its production of closely spaced upright branches. As these poorly attached branches grew and expanded in girth, the crown to split apart, often during snow-, ice-, and windstorms. It often happened to unpruned or poorly pruned trees when they reached 15 to 20 years of age.

In the past I counseled anyone who purchased a Bradford pear to buy a pruning saw as well. As described in the 1963 American Nurseryman article, the limbs of young trees must be selectively removed to produce branches with wider angles and stronger unions to develop a strong canopy.

To overcome this structural flaw, cultivars were developed that offered improved branching habits, such as ‘Aristocrat’ and ‘Chanticleer’, a 2005 Urban Tree of the Year by the Society of Municipal Arborists. Other cultivars were developed with narrower forms, such as ‘Capital‘, a U. S. National Arboretum release, that embodied the aesthetic and urban-tolerant traits of Bradford but offered applications in tight, confined locations.

This profusion of callery pear cultivars eventually led to another problem that had ecological consequences. In the past, Bradford pear rarely produced viable fruit because it’s self-infertile and cannot pollinate itself.  With the widespread planting of cultivars that were differed slightly genetically, the barrier to fertility and subequent fruit production was overcome. In some cases the callery pear understock of a Bradford pear would sprout, flower, and provide pollen. The fruits were consumed and dispersed by starlings, robins, and other animals to open, disturbed habitats where the progeny formed dense thickets.

Callery pears mature early—flowering at 3 years of age–and is one of the first trees to bloom in early spring. It’s also one of the last trees to lose its leaves. Callery pears are resistant to insects and diseases and their thorny stems and branches discourage deer-browsing. Interestingly, the “Survivor Tree” at the 9/11 Memorial is a callery pear that survived the September 11, 2001 terror attacks at the World Trade Center. In the context of the Memorial, it serves as a symbol of survival, recovery, and resilience.

Some states in the mid-Atlantic, southeast and midwest regions have declared callery pear an invasive, self-sustaining species that dominates and disrupts native flora. In South Carolina callery pear (and Bradford pear) is considered an invasive species by the  Southeast Exotic Pest Plant Council (SE-EPPC).

In the past I encouraged Bradford pear owners in our state to selectively prune the branches. Now that I witnessed large tracts of land throughout our state covered like a white fog in early spring, I encourage them to prune their trees at soil level.

The glorification and eventual demonization of  Bradford pear is the result of our unwillingness to foster biodiversity in our urban environments. While we make our communities more livable for people, we don’t do the same for trees. We disregard decades of arboricultural research and practices and continue to shoe-horn trees into unsustainable 4 square ft. tree pits that are better suited for traffic lights, signs, and streetlights than trees. It’s the survival of the fittest, and only a handful of tree species can exist in these inhospitable conditions. Bradford pear is one of them. This monocultural approach that relies on a single or limited number of species or cultivars had already led to catastrophic losses in our urban forests as witnessed by the demise of American elms to Dutch elm disease and ashes to emerald ash borer. However, we continue to rely on a handful of nearly indestructible species and cultivars that thrive in wretched conditions. Crapemyrtle (Lagerstroemia indica cultivars and hybrids), Chinese elm (Ulmus parvifolia), sawtooth oak (Quercus acutissima), and Chinese pistache (Pistacia chinensis) have supplanted Bradford pear as street-tough urban warriors.

Because cities are responsible for 70% of the world’s greenhouse-gas emissions but comprise only 2% of the world’s land mass (Time; Dec. 26, 2016/Jan. 2, 2017), we rely on trees to assume a greater role as ecological engineers in our urban communities. It’s important that communities create growing conditions that support a diverse population of native and noninvasive adapted tree species that provide environmental services and not ecological messes.

Bob Polomski  © 2017

Follow this Rx for your Spring fever

Despite “season creep,” Nature reminded me today that Spring has not officially arrived yet. At 7:26 a.m. it’s 38 degrees F and snowing. Despite this wintry mix, I still have Spring fever. It reminds me of the ”More Cowbell” Saturday Night Live sketch with “famed producer Bruce Dickinson” played by Christopher Walken. I find myself saying: “I got a fever! And the only prescription…is to get outside and garden.”

Fill your prescription for Spring fever after this unexpected unpleasantness passes with this short “to do” list of gardening activities.

Edibles

  • Buy seed potatoes and cut them into egg-sized pieces containing one or two eyes. Allow the cuts to dry and callous for a day or two beHyssop seedlings in flat 3_2_2016fore planting. Plant them when the soil temperature remains above 50o
  • Set out transplants of broccoli, cabbage, and cauliflower as well, up to four weeks before the last spring freeze.
  • Sow seeds of carrots, lettuce (leaf and head), garden peas, mustard, radishes, rutabaga, and spinach.
  • Sow warm-season vegetables in flats or trays—try eggplant, New Zealand spinach (a heat-tolerant substitute for spinach), pepper, and tomato.
  • Vegetables that resent any root disturbance, such as cucumber, muskmelon, summer squash, and watermelon, should be sown in individual pots or peat pellets.
  • Sweet potatoes are started from “slips”—shoots that sprouted from last year’s crop. Purchase them as transplants or start your own by placing a sweet potato in a glass half-filled with water. Place it in bright light. Detach the plants from the mother root when they are 6 to 8 inches long, pot them up, and then plant them in the garden about three weeks after the last freeze.
  • Sow parsley and dill. To encourage parsley seeds to sprout more rapidly, soften the seeds by soaking them overnight in warm water. Refer to the Planting Chart — Dates to Plant in SC for more information (hgic.clemson.edu).

Bulbs

  • After flowering, the leaves of your spring-flowering bulbs will turn an unsightly yellow. Temper your urge to remove the leaves, or braid them into attractive ponytails. The bulbs need the leaves to harvest energy that’s channeled to the bulb for next year’s flowers.

Perennials and Ornamental Grasses

  • Dig up, divide, and replant established perennials if they’ve become too crowded and flowering has been sparse. Some fast-growing perennials need to be divided between one and three years after planting—these include aster, astilbe, beebalm, boltonia, garden mum, garden phlox, rudbeckia, Shasta daisy, and many others. To avoid interrupting flowering, dig up summer- and fall-blooming perennials when the new growth is a few inches high.
  • Divide ornamental grasses before new growth emerges. Cut back the old culms to within 4 to 6 inches of the ground and use a sharp shovel or large knife to slice one or more wedges out of the crown. Immediately plant them elsewhere.

Shrubs 

  • Dense shrubs should not be planted close to the foundation or siding, or in front of foundation vents because they can obstruct air flow around and beneath your home, which can lead to moisture problems. Prune these shrubs or move them to another area in the landscape. If you move them to south- or west-facing walls to insulate your house from summer’s heat, keep them away from foundation vents and at least 4 feet from the foundation.
  • Keep shrubs away from the compressor on your split-system air conditioner. While the shade cast by the shrubs can reduce energy consumption, they should be planted far enough away so they won’t obstruct air flow or service.

Bob Polomski © 2017