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

Oriental Spruce Stands Up to Southern U.S. Heat and Humidity

Posted by Hugh on July 7th, 2016

Oriental spruce at UNC Charlotte Botanical Gardens

Oriental spruce (Picea orientalis) stands as a tall spire in the urban landscape. A mature tree may reach 50 to 60 feet tall and makes a narrow stature or footprint of 15 to 25 feet in spread. Lateral branches uniquely bend downward while the growing tips sweep gracefully upward.

Annual growth rate is slow at 12-15 inches. Two-thirds of the short dark green needles lay flat. Needles are lustrous on the upper surface with two prominent white bands on the underside. Oval-shaped 2 ½ inches long cones hang downward, bluish-black early and light cinnamon at maturity.

Oriental spruce is highly adaptable. It grows well in full or partial sunlight (6 hours recommended) and rooted in moist well-drained soils with a wide pH range. A 3-year and older established tree handles summer dry spells and rough urban environs. A nursery-grown tree transplants well in the early fall or late winter periods from container or balled and burlapped (B&B) stock. It is northern hardy to USDA hardiness zone 4 and with good heat tolerance in zone 7.

Their branch silhouette is unique. Few diseases and pests trouble this statuesque tree. Group several together as a windbreak or privacy screen or plant a single specimen in a prominent place in commercial and residential landscape. Where ground area is not plentiful, capture the vertical nature of this unique conifer.

Looking for an alternative to the oft-used Norway and Colorado spruces, try Oriental spruce. Dwarf and weeping cultivars are also available through e-commerce specialty conifer nurseries on-line.

Dreaded Japanese Beetles Are Back

Posted by Hugh on July 4th, 2016

Japanese beetles on rose bush

Severe intraveinal feeding of JB on Rose foliage

In many areas of the Eastern U.S. Japanese beetles (JB) devastate the foliage, fruits and flowers of more than 300 plant species, particularly those in the rose family (Rosaceae). Adult beetles are approximately 3/8 inches in length with a dark metallic green head and metallic dark tan wings. In the soil JB grubs appear “C” shaped and feed primarily on grass roots, but also will feed on roots of corn, beans, tomatoes, and strawberries.

Grub populations between 7 and 15 per square foot can cause significant damage to non-irrigated turf. Grubs chew off grass roots and large dead patches of lawn result. Dead lawn patches can be rolled back like a carpet to expose the grubs in adjacent green areas. Natural predators such as moles, shrews, skunks, and crows may be also observed digging up grubs and causing damage to home lawns.

Japanese beetle life cycle

Adults emerge from the soil in late June (zone 7) to early July (zone 5), feed, mate, and lay eggs. Adult beetles mate and feed over a 6 to 8 week period and gradually die off. Each JB female can lay up to 60 eggs. She lays eggs in the turf. By late September grubs have grown to almost full-sized (about 1 inch long). In the fall, grubs begin to move deeper and spend the winter in a dormant state 2 to 8 inches below the surface. They begin to feed again in late April.

Inspect areas of brown turf and search in adjacent green areas for grubs and pupae. Insecticides are needed to control grubs and adults. Irrigating after applying an insecticide improves its action in the soil. However, too much rainfall (or over-irrigation) following an application may dilute the amount of insecticide in the soil. Grub infestations should be checked one week after an insecticide is applied. If after 10 days the grubs are still alive, apply a different product. Always read the pesticide label carefully before using.

The best time to apply insecticides for grubs is from mid-July to the end of September. Granular applied insecticides are generally applied with a spreader. Insecticides that kill grubs include products that contain imidacloprid, or biorational insecticides that do not harm beneficial insects in turf areas such as Ortho Grub-B-Gone™ ((halofenozide) and Acelepryn™. Milky spore disease (Bacillus popillae) has met with mixed success in killing JB grubs. It is sold under the brand names: Japidemic Doom™ and Milky Spore®.

Foliar sprays of contact insecticides kill JB adults, such as carbaryl (Sevin®), acephate (Orthene™), pyrethrins, and pyrethroids. Examples include pyrethroid products such as cyfluthrin (Tempo, Bayer Advanced Lawn & Garden Multi-Insect Killer), bifenthrin (TalstarOne), and permethrin (Spectracide Bug Stop Multi-Purpose Insect Control Concentrate™ and others).

‘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.