What Grows There :: Hugh Conlon, Horticulturalist, Garden Advisor, and Photographer

‘Silk Tassel’ Sedge Shimmers In Shady Gardens

Posted by Hugh on July 1st, 2016

Carex-morrowii- ternofolia 'Silk-Tassel' at Ohio State Univ Gardens in Columbus, OH

Carex morrowii temnolepis ‘Silk-Tassel’ at Ohio State Univ Gardens in Columbus, OH

‘Silk Tassel’ Japanese sedge (Carex morrowii var. temnolepis) is an ornamental sedge from Japan (USDA hardiness zones 5 to 9). It is grown in shady areas for its narrow, variegated foliage. It grows slowly as a dense, grass-like clump to 12 -15 inches high and up to 2 feet spread.

Foliage bubbles up like a shimmering water fountain of fine-textured variegated foliage. Silk Tassel has ultra narrow, 1/8 inch wide thread-like leaves. Fine-textured leaves spill out over the ground. It has a soft, flowing, iridescent look and at first glance, may appear to be a sparkling, silvery green mound. A silvery white stripe at center with dark green margins runs the length of the narrow blade. Tiny greenish-brown flower spikes appear in mid-spring and are inconspicuous, supported on triangular stems. Silk Tassel is evergreen in the deep South.

Silk Tassel offers a great accent for patios and decks in decorative containers, or plant close together in masses. It looks super planted in a rock garden, perhaps nearby a dark igneous rock. It is easily grown in moist, moderately acidic, well-drained soils in partial day sunlight, preferably in morning or dappled light. Soil moisture is key, not too much(soupy) and never too dry.

Mix this fine textured beauty with bold leaf perennials such as hostas, lungworts (Pulmonaria spp.), brunneras (Brunnera) and other broad-leaved shade loving perennials.

Sedges may occasionally be troubled by aphids, and soil borne diseases such as Rhizoctonia. Deer leave most sedges alone.

Silk Tassel was introduced and named by Barry Yinger who brought it from Japan almost 30 years ago. It is primarily sold by mail order nurseries.

Yarrows Come In Many Size And Colors

Posted by Hugh on June 28th, 2016

Yellow flowering form of Yarrow

Salmon-Red Cultivar

Yarrow (Achillea millefolium) is a rhizomatous spreading perennial (USDA hardiness zones 3 to 9). The species originates from Europe and Asia and was introduced to America in colonial times. Today, yarrow is frequently seen naturalized along roadsides, fields, and gardens throughout the U. S.

Yarrow has fern-like, aromatic, foliage. Floral heads of 2-4 inch wide flattened corymb white flowers (and lots more colors) bloom from late spring through summer. Foliage emits a strong, somewhat spicy aroma that lingers when used in dried arrangements. Depending on cultivar, long-lasting flowers rise 1 ½ to 3 feet high.

Modern day cultivars possess strong stems, more upright forms and larger flowers. Flower colors range from pinks, reds, yellows, whites, and bicolor pastels. Showy flowers are irresistible to butterflies and make great cut and dried flowers.

Yarrow is a sun-loving, easy to grow, and performs well in any garden soils that is adequately drained. Where summers are hot and humid, plants are highly drought tolerant. Stems tend to flop over when grown in moist, rich soils. Protect plants from strong winds. Fertilize at planting time and in early spring as new growth begins to emerge.

Before flowering begins in late spring, reduce tall flowering cultivars by one-half to increase bloom count on more compact plants. Deadheading old spent flower heads will regenerate new blooms on stronger stems. Divide clumps every 2-3 years to maintain plant vigor. Yarrow spreads aggressively by rhizomes and self-seeding.

Stem rot, powdery mildew, rust and aphids are occasional problems, particularly where are poorly sited. Deer and rabbits stay away and the fern-like foliage tolerates air pollutants.

Herbal folklore: Achillea is derived from Achilles, hero of the Trojan Wars in Greek mythology, who used the plant medicinally to stop bleeding and to heal wounds.

‘Little Moonshine’ (new in 2015) – earlier and longer flowering (May-September); very compact 9-12 inches tall by 10-12 inches wide.

‘Peachy Seduction’ – 1 ½ – 2 feet in height and width lovely dense flat clusters of peach to rose-pink flowers; plant forms a tidy mound.

‘Strawberry Seduction’ (the Seduction Series™) – lovely densely packed strawberry-red/golden-yellow centers; dense dark green foliage on sturdy stems; 1 ½ -2 feet high and 2-3 feet wide.

‘Pomegranate’ -red-purple flowers atop 2-3 feet tall and 2 feet wide stems.

‘Pink Grapefruit’ –new cultivar in the Tutti Frutti series; large, slightly domed, deep rose-pink flower heads atop compact 2 foot stems.

‘Peggy Sue’ –2-3 foot tall, low-mounding plants with robust growth habit and apricot-orange blooms.

Nandinas Are Never Old-fashioned

Posted by Hugh on June 25th, 2016

Brightly colorful Nandina foliage in late winter in zone 6

Old-fashion species nandina in Jonesborough, TN

Nandinas in Planter Box in Winter at Biltmore Estate, Asheville, NC

Aka “heavenly bamboo”, nandinas (Nandina domestica) are broadleaf evergreen shrubs with several landscape attributes that include white spring flowers, color changing leathery foliage, and enormous clusters of colorful berry fruits in fall and winter (USDA hardiness zones 6-9).

This member of the Barberry family (Berberidaceae) is native to Japan, China and India. Foliage is variable, semi-evergreen to deciduous in northern areas in zones 6-7, and evergreen in zones 8-10. Some cultivars may die back to the ground during harsh winter and grow fully back by late spring.

Depending on cultivar, nandinas grow 4 to 8 feet tall and 2 to 4 feet wide with upright branching. Shrubs form erect, cane-like stems and compound leaves that some people may mistake as bamboo. Leaves comprise bi- or tri-pinnately compound that give it a fine textured appearance. They possess a rhizomatous rootsystem.

Depending on location, white panicle flowers appear in mid- to late-summer, 8-15 inches in length. Bright red ¼ inch berries follow in the fall and persist through winter. Cultivars ‘Leucocarpa’ and ‘Alba’ produce cream-colored berries. Deer leave nandinas alone. Fruits are rated poisonous to deer, other grazing animals and house pets.

Nandinas grow in average, medium moist, well-drained soils and in full sun to partial shade; they are shade tolerant. Soil pH may be either acidic to slightly alkaline. Leaves turn chlorotic in high pH (alkaline) soils.

Group or mass nandinas for optimum effect in shrub borders, home and building foundations, or open woodland areas. Nandinas are frequently utilized as low informal hedges in warm winter climates where foliage remains evergreen.

Note: nandinas are considered highly invasive in some southern states.

Popular Cultivars:

‘Firepower’ – popular dwarf, very compact 2 feet tall and wide shrub; lime-green foliage turns bright red in late fall thru winter; fruits sparingly.

Harbour Dwarf™ – compact 18 to 24 inches shrub; spring leaves emerge with coppery tints, green in summer, and bronzy-red in fall and winter; fruits sparingly.

Harbor Belle™ – dwarf, compact 18 to 24 inches shrub; spring leaves glossy green with pink tint, dark green by early summer; burgundy splashed in fall through winter; heavy load of bright red fruits in fall thru winter.

Gulfstream™ – compact growing 3-4 feet tall non-suckering shrub; medium green summer foliage turns orange-red winter in fall through winter; fruits sparingly; non-suckering.

Moonbay™ – sister seedling of ‘Gulfstream’, this dwarf variety grows 3-4 feet tall and wide; spring foliage emerges lime green, turns to medium green by early summer, and orange to red color in fall-winter; fruits sparingly; non-suckering.

Seasonal Mowing Height Of Home Lawns

Posted by Hugh on June 22nd, 2016

Red fescue lawn properly mowed

Fescue Lawn mowed too closely

The arrival of summer’s heat and dry weather is a clear sign to raise the cutting (mowing) height of your lawn grass. Every grass species have a recommended height at which it should be mowed for best health. The cutting height will change with the season. Location in the yard is also important. Here on some basic tips.

Recommended Mowing Heights of Grass Species:

Burmuda grass* – ½ to 1 ½ inches

Zoysia grass* – ¾ to 1 ½ inches

Centipede grass – 1 ½ to 2 inches

St Augustine grass – 2 to 4 inches

Fescue – 3 to 4 inches

A general rule to follow is to remove only one-third of a grass plant at any one mowing. For example, if you regularly mow your fescue lawn at 3 inches, allow it to grow to 4.5 inches tall before mowing.

In temperate areas (zones 5 to 7), most lawns are composed of tall fescues and/or bluegrasses. These grasses are usually mowed at 2 1/2 to 3 inches high. In partial shade fescue may be cut slightly taller @ 3 1/2 inches. In summer, mowing height should be raised a minimum of ½ to 1 inch taller than spring. Raising the mowing height results in deeper rooting and better drought and heat tolerance.

In summer’s heat and drought, if your lawn does not need mowing, DON’T!! Reduce mowing frequency in summer unless your lawn is irrigated and fertilized. Cool season grasses such as fescues and bluegrasses naturally grow slower (“summer dormancy”).

Growth of warm season grasses (burmuda, zoysia, centipede, and St. Augustine) also slow down when soil moisture is low. Raise the mowing height of bermuda grass and zoysia grass lawns as autumn approaches to protect the turf from winter injury.

Scalping (too close cutting) favors growing of undesirable grass species and weeds. For example, low mowing in early spring leads to invasion of weedy annual bluegrass (Poa annua). Scalping fescue lawns results in seedling burmuda grass, crabgrass, goosegrass, and other weeds.

Butterfly Weed – Long-lived Flowering Perennial That Nourish Monarchs

Posted by Hugh on June 21st, 2016

Long-lived Butterfly Weed at Chanticleer Gardens in Wayne, PA

Milkweed (Asclepias tuberosa), aka butterfly weed, is a tuberous rooted perennial native in the Eastern and southern U.S. (USDA hardiness zones 3 to 9). It grows in dry/rocky open woodlands, prairies, farm fields, and along roadsides. Individual plants typically grow as a clump to 1- 3 feet high and 1 ½ feet wide. Unlike many of the other milkweeds (Asclepias spp.), the sap is not milky.

For almost six weeks, from late spring into summer, clusters of vibrant orange to yellow-orange flowers (umbels) cover the plant canopy. The narrow, lance-shaped leaves are attached to hairy stems. Flowers are an important nectar source for many butterfly species and leaves are a key food source for the caterpillars (larvae) of monarch butterflies.

Butterfly weed freely self-seeds in the landscape. Prominent 3 – 6 inch long spindle-shaped seed pods break open when ripe and release multitudes of silky-tailed seeds which may carry a long way by wind. Seed pods may be utilized in dried flower arrangements.

Butterfly weed is a prairie survivor. It grows in average, dry to medium, well-drained soils in full sun. It does well in poor, dry soils, and established plants are highly drought tolerant. Shoots emerge late in the spring and grow rapidly. It frequently included in butterfly gardens, meadows, prairies, or other plantings.

Plants are easily started from seed, but may take 2 – 3 years before flowering. Do not try to dig up plants in the wild as they rarely survive transplanting due to their deep taproot system. Seedlings are best left undisturbed once established, usually after two years.

Few disease and insect problems trouble butterfly weed if grown in the right location. Wet, poorly-drained soil leads to rot rots. Leaves are susceptible to rust and leaf spots, particularly if the ground is overplanted. Pesticide use is rarely warranted. In medical circles the plant is commonly called “pleurisy root”, once used to treat lung inflammations.

Their bright orange flower clusters are among our showiest native wildflowers and picked for floral arrangements.

Celebrate National Pollinator Week

Posted by Hugh on June 19th, 2016

Bee Activity in Baltimore, MD Garden

Butterfly Quilt Display at NC Arboretum in Asheville, NC

June 20 – 26 is National Pollinator Week. National Pollinator Week is a time to celebrate pollinators and spread the word about what you can do to protect them.

Nine years ago the U.S. Senate unanimous approved and designated a week in June as “National Pollinator Week”. National Pollinator Week is supported by the U.S. Department of Agriculture and the U.S. Department of the Interior. It marks a necessary step toward addressing the urgent issue of declining pollinator populations.

For science teachers, this is an excellent way to get children involved. Pollinator Week has now grown into an international celebration of the valuable ecosystem services provided by bees, birds, butterflies, bats and beetles. Pollinators provide many ecosystem services. Choose the plants that can improve the plight of pollinators. There are lists of favorite pollinator and butterfly larvae feeding plants on this website and others. I highly recommend information published by the Xerces Society.

It’s time to celebrate! Check out: Find Events – It’s never too early to start thinking about an event at your school, garden, church, store, etc. Pollinators positively affect all our lives, supporting wildlife, healthy watershed and more… let’s Conserve and Protect it! Have a positive influence on our environment! Become a smart gardener.

If you’re hosting an event for Pollinator Week, you might want to register it with the Pollinator Partnership, which has a map of local events. http://www.pollinator.org/pollinatorweek/

Medical Benefits Derived From Gardening

Posted by Hugh on June 16th, 2016

Raised bed Garden (photo by Susan Morgan)

Raised bed Gardening Workshop (photo by Susan Morgan)

Making Air Plant Ornaments (photo by Susan Morgan)

For hundreds of years, home gardeners have realized that growing plants is good for you both physically and mentally. A story recently published in British tabloid The Guardian reports that many patients suffering with cancer, dementia and mental health problems can benefit from gardening. Doctors are more and more prescribing gardening for patients with cancer, dementia and mental health problems.

Outdoor spaces including gardens can reduce social isolation among older people as well as help patients recover and manage conditions such as dementia. GPs are advising some of their patients to spend more time outdoors to heighten their sense of well-being. The additional physical activity brings immediate payback and even promotes better sleep habits. It reduces social isolation and strengthens community bonds.

At a London clinic, a group of patients, doctors, nurses and local residents have created a network of food-growing gardens where patients learn how to grow food, which is then sold to the hospital to feed patients. A hospital in Salisbury designed special gardens which helped rehabilitate spinal injury patients. Outside spaces and gardens can serve to be important elements in improving end-of-life care, half of whom die in the hospital.

Dementia patients can benefit from being near a garden. One study reported a 19% reduction in violence in patients staying in garden sites; there was a seven-fold rise in violence in the non-garden sites during a year.

The therapeutic benefits of gardening don’t require taking lots of pills. Gardens can reduce levels of depression, loneliness, anxiety and stress, help improve older people’s balance, and benefit for a wide range of diagnoses including heart disease and obesity.

Credit: Photos courtesy of Susan Morgan, The Horticultural Link | thehorticulturallink.com | eatbreathegarden.com

Buttonbush Offers Year-round Interest

Posted by Hugh on June 13th, 2016

Cephalanthus occidentalis at Chicago Botanical Garden

Buttonbush Is Large Shrub

Buttonbush (Cephalanthus occidentalis), aka Button-willow or Honey Bells, is a medium to large native shrub with many fine landscape attributes. This unique flowering shrub is a favorite in attracting beneficial wildlife. It populates bogs, swamps and pond areas, as well as dry limestone bluffs in the eastern U.S. and southeastern Canada (USDA hardiness zones 5–9).

White pompom flowers are the unique ornamental asset. Tiny fragrant flowers appear in creamy white balls that are 1 – 1 ¼ inches in diameter in late spring (in Philadelphia, PA) to early summer (northern New England). Long projecting styles from the flower heads gives it a distinctive pincushion appearance. Flower heads mature into hard spherical ball-like fruits containing tiny two-seeded nutlets. Dried seed balls persist all winter long.

Give the buttonbush room to grow. This multi-stemmed deciduous shrub grows 6-12 feet tall and 4-7 feet wide. On older shrubs stems and trunks appear twisted when twigs are bare of leaves in winter. Pruning is usually unnecessary and is done in early spring to shape or reduce plant dimensions. Old neglected plants may be revitalized by cutting them back near to the ground in late winter.

Buttonbush has year-round garden interest with late spring flowers, summer and fall foliage, and fall/winter fruits. Narrow oval green deciduous leaves emerge in spring and turn shades of red in fall. It has no serious disease or insect problems. Foliage is poisonous to humans and livestock; deer may snack on new spring growth.

Buttonbush is best planted in wet, humus-rich soils and in full sun to part shade. Favorite landscape sites include in rain gardens or the edge of ponds. Established plants after 1-2 years are moderately drought tolerant.

Fragrant flowers attract butterflies, bees, and hummingbirds for nectar. Leaves are the larval host for some butterfly species. Waterfowl, quail, and other birds feed on the nut-like seeds. Cut flowers look great in fresh summer bouquets or in dried arrangements.

Japanese Snowbells Worth A Try

Posted by Hugh on June 10th, 2016

Mid-spring flower

Styrax japonicus ‘Pendula’ at Atlanta Botanical Garden, Atlanta, GA

Japanese snowbells (Styrax japonicus) is a graceful, slow growing, low branched spring flowering tree. At present snowbells are not popular with U.S. gardeners , mostly because of unavailabliity (USDA hardiness zones 5-8). Snowbells are lovely understory trees, similar to our native dogwoods (Cornus florida). Small, pendulous, slightly fragrant, bell-shaped white flowers appear in May. Small white ½ inch oval-shaped drupe fruits are ornate by late summer.

Site selection is very important! At first spring warmup, snowbells often leaf out too early. They’re are best planted on the north side of a home or building to slowdown spring leaf emergence and possible frost injury to leaves and flower buds. Snowbells grow in full to partial sunlight and are suited to moist, mildly acidic, compost-rich, well-drained soil. Supplemental watering is advised the first two years for establishment. Fertilize in early spring with an organic or slow-release fertilizer designed for flowering shrubs.

Snowbells reach mature heights and widths of 18 to 30 feet, a perfect size for most urban gardens. Cracks or fissures over the gray bark of older branches reveal an orange inner bark, a unique feature on mature specimens during winter. Elliptic-ovate, glossy, 2 to 3 inch long, deep green summer leaves stay generally blemish-free. Most years, fall leaf color is of no consequence, sometimes turning clear yellow.

Snowbells have few disease or pest problems when properly sited and cared for. Fragrant flowers attract hundreds of bees and butterflies.

Notable cultivars:

‘Pink Chimes’ – pink, fragrant flowers on slightly weeping.

‘Emerald Pagoda’ – slightly larger star-like flowers, graceful weeping form.

‘Carillon’ (same as ‘Pendula’) – white with showy yellow stamens flowers and slightly weeping.

In most areas snowbells are still a collector’s plant, rarely sold at local garden centers. E-commerce nurseries are good sources.

Other Snowbell (Styrax) species:

American styrax (S. americanum) – cold-hardy and shrub-like.

Fragrant snowbell (S. obassia) – exfoliating (peeling) bark for winter interest.

Three Native Landscape Grasses To Try

Posted by Hugh on June 7th, 2016

Leymus grass at Atlantic Botanical Gardens

Blue Lyme Grass at the Atlanta Botanical Garden

Nassellia tenuissima in UT Gardens, Knoxville, Tennessee

Nassella tenuissima in UT Gardens, Knoxville, Tennessee

These three native grasses are easy to establish in average, dry to medium moist, well-drained soils and in full sun. They tolerate a wide range of soils including dry rocky sites, and are exceptionally drought tolerant. Figure on 1 to 2 years for each to become fully established.

Blue Lyme Grass (Leymus arenarus ‘Blue Dune’) is a vigorous spreading cool season grass, 24-30 inches tall, with steel blue foliage and arching growth habit. Blue Lyme is a vigorous grower in warm areas of the U.S. (USDA Hardiness zones 4-10).

Tall flower spikes appear in mid-summer. It grows in a wide range of soils, wet to dry, and in either full sun to partial shade. It grows less aggressive in dry, clay soils. Foliage remains evergreen in zone 8-10; otherwise, blades take on a beige tint in early fall.

Prairie dropseed (Sporobolus heterolepsis) is a clump-forming, warm season, perennial grass found in prairies, glades, and open land areas native to the Midwest U.S. (USDA hardiness zones 3-9). Light airy inflorescences (flower panicles) rise several inches above the fine textured, deep green foliage in September and October.

Prairie dropseed forms mounds of arching foliage, each 1 ½ feet tall and 3 feet wide. Leaf blades turn a golden fall color with orange hues and later to light bronze over winter. Flower panicles have pink and brown tints, and emits a hint of coriander or popcorn fragrance. Tiny rounded mature seeds drop to the ground from their hulls in autumn and serve up a morsel for seed feeding birds. It generally does not self-seed in the garden.

Mexican feather grass or silky thread grass (Naasella tenuissima) is a light airy ornamental grass that flutters in the slightest of breezes (USDA hardiness zones 5-10). Plant in groups of 5 or more to create waves of fine foliage. In the first year irrigate over the first 2-3 months until established and is highly drought tolerant from this point on.

Their green silky inflorescences will soften landscape areas from late spring into late summer, the plumes swaying in the slightest breeze. Plumes turn brown in late summer. Remove winter dead growth at the start of spring.