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

Our Native Bumblebees In Trouble

Posted by Hugh on February 7th, 2018

Native bumblebee (Bombus impatiens) on coneflower

Bumblebee on flower

In 2017 the U.S. Fish and Wildlife Service recognized 10 more animal species as Endangered Species, giving them protections under the Endangered Species Act of 1973. These 10 species include 7 species of bees. Endangered status would afford the rusty-patched bumblebee protection under federal law.

Honeybees, which are not native to the U.S., build and live in the same nest (hive) for many years. Bumblebees, on the other hand, build their nests in the ground, hollow crevices of trees, and other places. Populations of rusty-patched bumblebees were once widespread across the U.S. and Canada. Today their numbers their populations are spotty and limited to the northeastern quarter of the U.S. and Canada.

Bumble bees face many threats including habitat loss, disease, pesticide use, and climate change. Unlike honeybees which inhabit large (>10,000 individuals) perennial hives, bumble bees produce smaller annual colonies of 50-1,500 individuals. Due to their smaller annual population sizes, life cycle, and genetic makeup, they are uniquely susceptible to extinction.

Bumblebees typically nest underground as well as overwinter in undisturbed ground – one that is not planted or mowed. Bumblebees may also nest in compost piles, woodpiles, stone walls, or empty bird houses.

According to the Xerces Society, here are some things that gardeners can do to help bumblebees:

Plant your garden to start blooming early and finish late. Provide bumblebees with pollen and nectar from late winter through early autumn.
Choose flowers of plant species native to your region that the bumblebees evolved alongside with. Plant species from around the world may be beneficial as well. Flowers should closely look like open pollinating species. Don’t plant varieties with double petals that make it hard for the bumblebee to access the pollen.
Purple, blue and yellow flowers attract bumblebees. Bees cannot see the color red.
Avoid using pesticides in your flower garden.
Learn and understand the natural habitat of bumblebees
Involve gardening friends and neighbors to create bee habitats.

For additional tips on conserving bumblebees, visit the Xerces Society website: http://www.xerces.org/bumblebees/

Controlling Slugs and Snails

Posted by Hugh on February 4th, 2018

Slug feeding on hosta

Slugs on pavement

Slugs and snails are common pests of many common garden plants. They are particularly troublesome in shady woodland areas. They crawl across leaves and leave a slimy residue over the leaf surface. They feed primarily at night. Ecologically, their niche is to decompose organic matter. During the daytime hours they hide under leaves, mulch, rocks, stepping stones, and other dark areas.

Slugs and snails can be removed by handpicking. Favorite perennial plants are hostas, lungworts (Pulmonaria), and Siberian bugloss (Brunnera) are susceptible perennials as well as many vegetable and herb plants.

Popular control measures include slug and snail control baits that contain iron phosphate, such as Sluggo™, Schultz™ Slug & Snail Bait, and Bayer Advanced™ Snail & Slug Killer Bait. Baits containing metaldehyde are also effective, but are harmful to pets and birds. Read label directions before using.

Popular homemade remedy is the “Beer Bath”. Fill a shallow container with beer and submerged it in the ground with the rim even with the soil. Snails and slugs are attracted to the beer odor, fall in, and drown.

Sprinkling diatomaceous earth around the plants also work. The sharp crystals pierce their thin jelly-like skin resulting in dehydration and death. Diatomaceous earth must be reapplied after a rain or watering.

Other short term remedies that deter snails and slugs include:

limestone, cinders, coarse dry sawdust, gravel or sand.
Epson Salts sprinkled on the soil will deter slugs and adds Magnesium nutrient to feed garden plants.
Spread table salt around your plants. Salt dries them out so they won’t go near it.
Collect human, dog, or cat hair and place around your susceptible plants; slugs and other critters will stay away.
Plant specific plants around the edge of the garden which slugs hate the smell. List of anti-slug plants are: mint, chives, garlic, geraniums, foxgloves, and fennel.
Mix 1 part ammonia to 3 parts of water into an aerosol bottle and give slugs a squirt.

Best Annuals Of 2017

Posted by Hugh on January 31st, 2018

Each year Greenhouse Grower* magazine compiles a listing of the best annuals selected by field garden staff and garden visitors to 19 public and seed company trial gardens across the U.S. Talleying the resuts, thirty-five (35) varieties appeared more than once, with Salvia ‘Mystic Spires Improved’ and Alternanthera ‘Purple Prince’ appearing five times.

Before proceeding further, keep in mind that this a non-scientific poll as not every variety was planted or evaluated at each site. Climate and field conditions were major variables at each location.

See chart below: * Varieties appearing three times; ** Varieties appearing four times; *** Varieties five times or more

Varieties Appearing On Top Performer Lists More Than Once:

Alternanthera ‘Purple Prince’

Alternanthera ‘Purple Prince’***

Begonia ‘MegaWatt Pink Bronze Leaf’

Begonia ‘MegaWatt Red Bronze Leaf’*

Calibrachoa ‘MiniFamous Neo Orange + Red Eye’

Calibrachoa ‘Superbells Rising Star’

Canna ‘CannovaBronze Orange’

Coleus ‘Flame Thrower Salsa Verda’*

Coleus ‘Main Street Michigan Avenue’

Dianthus ‘Jolt Pink Magic’

Echinacea ‘Sombrero Granada Gold’

Echinacea ‘Sombrero Lemon Yellow Improved’

Echinacea ‘Sombrero Sangrita’

Echinacea ‘Sombrero Sangrita’

Ersyimum ‘Bowles Me Away’

Ersyimum ‘Cheers Florange’

Ersyimum ‘Cheers Sunkissed Amethyst’

Helianthus ‘Autumn Gold’

Lantana ‘Havana Sunset’

Miscanthus‘Bandwidth’

Pennisetum glaucum ‘Copper Prince’

Pentas ‘Lucky Star Deep Pink’

Pepper (Capsicum) ‘Midnight Fire’

Pentas ‘Lucky Star Lavender’

Pepper ‘Midnight Fire’*

Petunia ColorRush Pink’**

Petunia ‘Supertunia Bordeaux’*

Petunia ‘Supertunia Lovie Dovie’**

Petunia ‘Supertunia Mulberry Charm’

Petunia ‘Supertunia Vista Bubblegum’

Petunia ‘Supertunia Vista Fuchsia’

Salvia ‘Mystic Spires Improved’***

Salvia ‘Rockin’ Playin’ The Blues Improved’

Salvia ‘Rockin’ Deep Purple’

Thunbergia ‘Lemon A-Peel’*

Verbena ‘EnduraScape Pink Bicolor’

Zinnia ‘Double Zahara Raspberry Ripple’*

*Greenhouse Grower magazine (November 2017 issue), Meister Publications

Seven Shrubs That Bloom In February*

Posted by Hugh on January 27th, 2018

Daphne odora ‘Aureomarginata’ at Biltmore Estates, Asheville, NC

Hamamelis x ‘Primavera’ in February 2017

If you garden in zones 6 to 8, there are a number of shrubs that bloom in the wintry month of February. Usually, a warm period lasting a few days to a week may spur flower buds to open. Nightly lows may cause some flower injury, but additional flowers soon follow. All seven listed below are long-lived and are highly dependable.

Carolina Jessamine (Gelsemium sempervirens) – Sweetly scented, golden yellow flowers cover the glossy, fine textured foliage from February to April. Moderately deer resistant (zones 6-9)

Chinese Witchhazel (Hamamelis x intermedia) represent crossing two Asian witchhazels (H. japonica x H. mollis). Shrubs grow 6-12 feet tall and wide and may sucker freely at the base. Recommended cultivars are ‘Diane’, ‘Jelena’, ‘Orange Beauty’, ‘Primavera’ and ‘Westerstede’. Moderately deer resistant (zones 5-9)

Chinese Paper bush (Edgeworthia chrysantha) is a deciduous suckering shrub that typically grows to 4-6 feet tall and as wide. Short-petioled, lanceolate-oblong, dark green 3-5 inch long leaves are attractive in the woodland garden (zones 6-9).

Winter Honeysuckle (Lonicera fragrantissima) –small fragrant white flowers appear in midwinter on this 10-12 foot tall vigorous shrub. Note: rated “invasive Florida and Texas where winter temperatures are mild; not so much in zone 7 and colder areas further north (zones 4-8).

Winter Daphne (Daphne odora) 3-4 feet tall evergreen, densely branched shrub with rose-purple or white, fragrant flowers in mid- to late winter (zones 7-9). Fragrant 2 inch long tubular flowers are a half-inch across and are usually white but may include pink or lavender hues; flowers bloom in winter and early spring.

Fragrant Wintersweet (Chimonanthus praecox) produces highly fragrant yellow/slight red blotched flowers in late January is at home in a rich, acidic, moist, well-drained soils in part to full shade. 12 feet by 10 feet deciduous shrub; established shrub is moderately drought tolerant (zones 6 to 9).

Sweetbox (Sarcococca hookeriana ‘Humilis’) is a suckering 4-6-foot evergreen shrub with fragrant white flowers set against glossy boxwood-like foliage. It spreads very slowly by stolons in a shady landscape area (zones 6 to 9).

* Blooms are visited by early pollinating native bees and butterflies. Hungry bees will be pleased to find nectar in late days of winter.

Uniquely Different Monkey Puzzle Tree

Posted by Hugh on January 24th, 2018

Monkey Puzzle Tree in Vancouver, BC

Closeup of scale-like foliage

Monkey puzzle tree or Chilian pine (Araucaria araucana) is an evergreen conifer that is native to forested volcanic slopes of the Andes Mountains in Chile and Argentina (USDA Zone 7b-11). It is the national tree of Chile. Monkey puzzle typically grows to 60-70 feet tall and 30-35 feet wide, but may reach heights greater than 100 feet in its native habitat.

It displays a unique loose pyramidal form when young, but develops a rounded canopy along with loss of the lower branches as the tree ages. Horizontal, upward-arching branches are arranged in whorls around the trunk. Bark is gray-brown and ridged.

On the straight trunk, 2-inch long evergreen leaves are glossy, dark green, triangular-shaped, sharp tipped, and closely overlap one another. Individual leaves are leathery and may persist for 10 – 15 years. The horizontal branches are produced in tiers and develop few side branches.

Trees are dioecious (separate male and female trees). The female cones are globular and up to 8 inches in diameter; male cone is cylindrical and up to 5 inches long. Seeds (pinones) are edible and reminiscent of pine nuts.

It is best grown in deep, moderately fertile, evenly moist, well-drained soils and in full sun to part shade. Trees perform well in a variety of different soils as long as sites are well-drained. Trees perform much better in mild summers than in hot climates. In northerly areas, trees may be grown in containers and brought indoors overwinter in bright indirect sunlight.

The tree is rarely troubled by serious insect or disease problems. Needle necrosis and leaf spots. Mealybugs, scales and thrips are occasional pests.

Monkey puzzle is related Norfolk Island pine (A. heterophylla), a popular house plant seen for sale at garden shops during the winter holiday season in the U’S. and Canada.

Winter Honeysuckle Totally Ignored In The landscape

Posted by Hugh on January 21st, 2018

Fragrant honeysuckle in February at Biltmore Estates in Asheville, NC

Glossy brown bark noticeable in winter months

Winter honeysuckle, aka fragrant honeysuckle (Lonicera fragrantissima) is a treasured old-fashioned shrub (USDA hardiness zones 4 to 8). It can still be found growing in older urban neighborhoods and parks. Winter blooming fragrant honeysuckles are a harbinger of spring. Budded branches may be cut and forced indoors.

This vigorous durable shrub grows 6 -10 feet in height and width. Many opt to limb up the lower branches to view the glossy brown wood. Its overall vigor is incredible and gardeners also choose to cut it off at the ground every 5-10 years (after blooming has finished). It is rarely sold in garden centers. Cuttings root easily and you can pass-along this heirloom shrub to gardening friends.

Frequently, here in the mid-South (zones 6 and 7), the small, creamy flowers appear during a warm spell in January – February. It continues to bloom on and off through March. The strong lemony fragrance catches your nose. The spring-summer foliage is blue green and develops little in fall color. Further south (zones 7 and 8), the foliage is almost evergreen.

Fragrant honeysuckle grows in average, dry to medium, well-drained soil, and in full sun to partial shade. Feed with 10-10-10 or equivalent granular fertilizer in early spring. Mulch honeysuckles and other spring blooming shrubs in early spring for weed management and to conserve soil moisture.

While potentially susceptible to a number of disease and pest problems, fragrant honeysuckle is very tough and outgrows most troubles. Pests include aphids, scale, sawfly, whitefly, and webworm. Powdery mildew may show up if summer weather is unusually wet. Hungry bees are especially glad to find any flowering plant in late winter days. The warm sun draw them out in search of nectar. Months later, it may attract hungry birds to the berries if any develop.

Important: Winter honeysuckle is a “true” honeysuckle. It is not listed invasive in Tennessee and Virginia, but North Carolina and Texas forbids new plantings. Since it blooms so early in the year, e.g., compared to most honeysuckle species, few fruits or seeds develop. In southern locales where winters are mild, it seeds in prolifically.

Landscape use: clipped or informal hedge, screen or background border shrub.

Small Landscape Tree – Try Chinese Pistache

Posted by Hugh on January 17th, 2018

Compound leaf

Pistacia chinensis

Chinese pistache tree (Pistachia chinensis) is an underplanted small 30-35 foot landscape tree native to China, Taiwan and the Philippines (USDA hardiness zones 6b-9). It is related to the edible nut pistache tree (Pistachia vera).

Foliage consists of pinnate compound, dark green leaves (to 10 inches long), each leaf typically having 10-12 lanceolate leaflets (to 4 inches long). The tree displays a fine leaf texture. The small leaflets are an easy clean-up at raking time. Foliage is aromatic when bruised. The eye catching fall color is crimson red, bright orange, or occasionally yellow.

This tree species is dioecious, e.g a single tree is either male or female. Pistache blooms in April but is not a standout compared to all shrubs and trees flowering at this time. Female flower clusters are nearly twice as wide as males. The non-edible fruits turn red in summer before ripening to blue-purple in winter. However, the berries (drupes, ¼ inches in diameter) are a food source for birds. Gray-brown bark on older trees peels to reveal salmon inner bark.

Chinese pistache grows in moist, compost rich, well-drained soils in full sun. It prospers in full sun but can handle partial shade. Verticillium wilt can become a serious problem in poorly drained soil. A 2-year old established tree tolerates summer heat, drought, and moderate air pollution. Annual pruning in early years is essential to maintain a symmetrical tree with good form.

If you are concerned about berries dropping on walkways, select a fruitless male clone, P. chinensis ‘Keith Davey,’ a 35-foot high tree with a crown diameter of 30 feet.

Four Top Rated Coreopsis You May Not Know

Posted by Hugh on January 14th, 2018

Coreopsis ‘Gold Standard’

C. ‘Gold Standard’

In 2016, Mt. Cuba Center in Greenville, Delaware reported the garden performance of 13 different perennial coreopsis (tickseed) species, hybrids, and related cultivars native to the eastern U.S. Over a period of three years, plants were assessed for their habit, floral display, disease resistance, and longevity. In the trial many popular tickseed cultivars performed poorly because of disease and winter survivability.

Four new selections were recognized and named because of their outstanding performance in the trial. The following plants, listed in order starting with the highest rated, are among the top-performing coreopsis.

‘Summer Sunshine’ coreopsis (C. palustris ‘Summer Sunshine’) is the highest-rated coreopsis in the 3-year trial. Vigorous mounds of foliage grow to 30 inches tall and remain lush, sturdy, and dense all season long. The attractive foliage erupts in late September with a sea of golden yellow flowers with dark central cones. The amazing display lasts for six weeks, providing an important late-season food source for pollinators. ‘Summer Sunshine’ is a rhizomatous selection that slowly increases in size by 2½ feet over three years. It has superior growth habit and disease resistance.
‘Flower Tower’ coreopsis (C. tripteris ‘Flower Tower’), appropriately named, towers over the competition at an astonishing 8 feet tall. This tall cultivar does not flop with thick, sturdy stems, standing up to the strongest winds. ‘Flower Tower’ was the tallest coreopsis in the trial and has the largest flowers (2½”). During the month of August, they create a wonderful display swaying atop the lofty stems. ‘Flower Tower’ is perfect for large-scale landscapes, but a challenge in average sized gardens. C. tripteris ‘Flower Tower’ is a rhizomatous selection that spreads very slowly– about 2 feet over 3 years.
‘Gold Standard’ coreopsis (C. tripteris ‘Gold Standard’) is a superior selection of tall tickseed (C. tripteris). C. tripteris grow typically to nearly 7 feet tall, has a floppy growth habit and subpar floral display. But ‘Gold Standard’, collected in Alabama by Mt. Cuba Center, is slightly shorter (5½ feet’ tall) and incredibly sturdy. In late July, multitudes of bright yellow flowers appear above the vigorous foliage, reaches its peak in mid-August, and floral display lasts over two months. ‘Gold Standard’, in fact the whole species exhibits excellent disease resistance, particularly powdery mildew, downy mildew, and leaf spot, that plague other coreopsis. ‘Gold Standard’ is a rhizomatous cultivar that spreads slowly– about 2’ over three years.
C. ‘Last Dance’
‘Last Dance’ coreopsis (C. integrifolia ‘Last Dance’) is a fall-blooming tickseed that has a superior uniformly compact habit over other forms of C. integrifolia. ‘Last Dance’ emerges slowly in spring and does not reach 1 foot tall until June, and is just 2 feet tall. The gold colored flowers are extra-large (2 inches) with thick pleated petals. It is the latest coreopsis to flower in October.

View the entire research report on Coreopsis on the MT Cuba Center website.

Photos furnished by MT Cuba Center, Greenville, DE.

Pest Alert: Deep Freeze Negatively Impacts Hemlock Adelgid Populations in the Smokies

Posted by Hugh on January 12th, 2018

Hemlock adelgid

GOOD NEWS! The recent cold snap is having a negative impact on the invasive hemlock wooly adelgids in the Smokies. Since 2002 this insect has killed millions of hemlock trees in the U.S. Biologists in the Great Smoky Mountains report that the recent spell of frigid temperatures has killed off overwintering hemlock adelgids.

Over 15 years ago, the hemlock woolly adelgid (HWA) invaded the Great Smoky Mountains National Park. This tiny Asian insect has killed millions of hemlock trees in the Eastern U.S. The pest gets its name from the white woolly coating that covers and protects the nymphs while they feast on hemlock trees.

Wooly adelgids complete a lot of their life cycle over the winter months. The severe dips in temperatures this winter are negatively effecting populations in the Northern areas of the U.S. and Canada. Insect mortality occurs when temps go down to 4 – 5°F.

The hemlock-killing bugs had been rebound the last couple of winters. A similar deep freeze back in 2014 also penetrated the insects’ woolly protection. “The big ‘polar vortex’ blast in 2014 and 2015 really helped us out with the adelgid. We had those prolonged weeks where the temperature was below zero in the higher elevations and killed a lot of them,” says NPS forester Jesse Webster.

Last year’s drought saw big population increases in HWA. “We really can benefit from some hard freezes in dry weather. Snow and ice can insulate insects. When they are directly exposed to the extremely cold air, that’s when their mortality rates are really high” says Webster.

Credit: this information originated from a news report from WBIR-TV in Knoxville, TN and has been edited.

Key Landscaping Tips

Posted by Hugh on January 11th, 2018

Hybrid rhododendron

Soil preparation

To develop a successful landscape plan, first do a walk-a-round before you start digging and planting. Record your landscape’s sun patterns, soil types, wind and water movement. This information will help you select the kinds of plants that will prosper under existing conditions.

Sun exposure shifts daily and seasonally. Observe the garden at different times to gain a better understanding of light exposures. Particularly note areas that receive full day sun or full shade. What percentage of existing trees and shrubs are deciduous and evergreen. Under deciduous shade, the fall and winter landscape may bathe in sunlight. In areas with partial sun exposure, identify where sunlight strikes an area at what time(s) of day as well as seasonally.

Soils may vary from one area of a landscape to another. Dig test holes in a variety of locations to determine the texture and color of soils. Is the landscape composed of sandy or loamy soils? Does it contain lots of clay? Soil type and drainage go hand-in-hand and impact the types of plants that should prosper in your landscape. Sandy soils drain very quickly, while clay soils are slow to drain. Many plants are also limited by soil pH, so it is a good idea to have the soil analyzed.

Water and Soil Drainage. In addition to soil type, topography and physical structures influence soil moisture. Low spots and areas surrounding downspouts tend to be wet, while the area beneath an overhang is commonly dry. Walk the garden after a rain to see where water collects and make note of seasonal rainfall patterns in your area. Do your region frequently experience seasonal drought; is your summer climate hot and humid? Are your winters generally snow covered or will ice storms damage tree branches?

Wind. Exposure to wind may vary considerably across a landscape. Some areas are likely exposed to strong winds while others may be protected by buildings, structures, or tall shrubs. For example, broadleaf evergreens such as camellias, rhododendrons, daphnes, and pieris are sensitive to drying winter winds. Understanding wind patterns will aid in positioning new plants at planting time.

Wildlife. What birds and animals are indigenous to your neighborhood? Do critters cause damage to plants? Consider deer, rabbits, raccoons, squirrels, moles, voles (field mice) which may relish your landscape and garden plants.