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

Getting Rid Of Poison Ivy

Posted by Hugh on July 15th, 2015

Some pesticides to manage poison ivy

Poison Ivy Overrunning Rose Bush

Poison ivy (Toxicodendron radicans) is a woody perennial vine or small shrub that is grows wild in fields, woodlands, and home landscapes. As a vine, poison ivy has 3-leaf (trifoliate) compound leaves; leaf margins may be entire or tri-lobed. It is frequently misidentified as Virginia creeper (Parthenocissus quinquefolia), which has compound leaves with five rather than three leaflets. Poison ivy aggressively attaches itself to trees or other structures with hairy, aerial roots borne protruding along stems.

Poison ivy grows rapidly by underground rhizomes and seeds. Seeds are distributed by birds and other animals that eat the small fruits. Poison ivy often becomes entangled in shrubs and groundcovers making it difficult to control without harming desired plants growing nearby.

To eradicate poison ivy from your property, dress protectively. Wear a long-sleeved shirt, long pants and plastic (not cloth) gloves. Launder the clothing separately after spraying and discard the plastic gloves.

A number of chemical herbicides contain the following ingredients: glyphosate, triclopyr, 2,4-D amine, dicamba and mecoprop. Some garden centers sell a 3-way herbicide containing 2,4-D amine, dicamba and mecoprop.

Herbicides are applied to leaves and cut stems and translocated through the rest of the plant, killing entire shoots and roots. Repeated applications are often necessary, up to three times over a 2- month period before you successfully eradicated poison ivy, so be patient.

Herbicides work better when you spray at the right time. Poison ivy is most sensitive in mid-summer after leaves have fully expand and before autumn leaf color starts. Glyphosate (Roundup® or equivalent) offers the best control when mixed as a 2% solution (approx. 2 TBSP per gallon).

In residential lawns, a 3-way herbicide may be applied to tall fescue, bermudagrass, zoysiagrass, St. Augustinegrass and centipedegrass for poison ivy control. Glyphosate, 2,4-D amine, dicamba, mecoprop and triclopyr are translocated through grass blades and cut stems to grass crowns and roots. Repeat spraying as needed.

Always read and follow pesticide labels.

ARS Selects ‘Oso Easy Lemon Zest’ Rose For Award of Excellence

Posted by Hugh on July 13th, 2015

‘Oso Easy Lemon Zest’ Rose From Proven Winners

The American Rose Society (ARS) announced at the 2015 National Conference that Proven Winners received the Award of Excellence for its Oso Easy Lemon Zest shrub rose. To receive this honor, a rose must prove its toughness and beauty in six different no-spray trial locations across the U.S.(USDA hardiness zones 5-9).

“Oso Easy Lemon Zest rose is a healthy-growing, self-cleaning rose that does not fade to white. It’s one of our favorite roses and one of our top sellers,” according to Tim Wood, Product Development, Spring Meadow Nursery.

Oso Easy Lemon Zest rose was developed by Chris Warner, the highly acclaimed rose breeder from Shropshire, England. After years of trials and evaluation, Oso Easy Lemon Zest rose has lived up to the highest standards. This rose exhibits a very high level of disease resistance. Its sunny, canary yellow flowers do not fade to white as they age. It is hardy and free-flowering, self-cleaning with attractive glossy green foliage.

This shrub rose prefers moist, well-drained soils and in full sun. It grows well in containers, or group several together for a landscape show. Its vibrant color makes Oso Easy Lemon Zest a super focal point in a garden or patio setting.

Spraying and pruning is generally not needed, but this shrub rose may be shaped in early spring before leaf out. Fertilize in early spring and again in early summer with any brand of rose foods sold at local garden centers.

Let Gaura Flutter In Your Garden This Summer

Posted by Hugh on July 12th, 2015

White flowering Gaura

Dark Pink Gaura at Biltmore Estates in Asheville, NC

What first catches your eye about perennial gaura (Gaura lindheimeri) is its light airy white (or pink) flowers (USDA hardiness zones 5 -9). Orchid-like blossoms are perched atop long thin stems. A faint breeze makes flowers flutter like a cloud of small butterflies above the dark green foliage. Also called wandflower, this Texas native is exceptionally heat and drought tolerant.

Don’t let its delicate appearance fool you. Many plant shoppers may pass it by at garden centers in the spring. It blooms non-stop all three growing seasons. Gaura is easy to grow and very low maintenance. Use it to edge a perennial or annual flower bed or group 3 or more in a rock garden or a container. Autumn foliage takes on a maroon tint.

New white and pink blooming cultivars continue to arrive at local garden centers. Most (not all) cultivars grow 2 ½ to 4 feet high. Among the best:

‘Whirling Butterflies’ has loose sprays of white flowers, lightly pink tinged.

‘Siskiyou Pink’ is a smaller cultivar; spring flowers start out pale pink and darken later in the summer.

‘Crimson Butterflies’ is a compact cultivar with dark red-pink blooms.

‘Ballerina Blush’ (pale pink blooms) and ‘Ballerina Rose’ (rose pink) grow only 12 – 18 inches tall.

Gaura does not always overwinter reliably. Good soil drainage is a must! Plants do not like soggy ground in winter. Gaura has a long taproot system, so is very drought tolerant. Its fertilizer needs are minimal.

Gaura rarely is troubled by disease or insect problems; leaf spots and powdery mildew may pop up if summer weather is exceptionally wet or plants are over-irrigated.

Colorful Oleanders For Hot Summer Climes

Posted by Hugh on July 9th, 2015

Oleander in North Texas garden

Oleander (Nerium oleander) is an attractive evergreen shrub for warm climates. Indigenous to the Mediterranean region, it is popular in warm regions of the U.S., namely in western, coastal, and southern states (USDA hardiness zones 8-11).

Oleander prefers moist, well-drained soil and a sunny landscape site. Established shrubs withstand dry and windy conditions along coastal areas. Brightly colored flowers, depending on variety, range from red, purple, pink, lilac, salmon, yellow, and white. A few flaunt variegated foliage. Oleander blooms in spurts from late spring to early fall.

Oleanders grow 8-15 feet in height and 5-10 feet in width. Some cultivars can be trained into small trees which may get 20-25 feet tall. Overall floral fragrance differs from one plant to the next.

Plant nursery-grown container plants in spring, summer, or fall. For a hedge space oleanders 6 to 12 feet apart, depending on cultivar size and vigor. Water plants during the summer if weekly rainfall falls below 1- inch.

Prune oleander immediately following its main bloom period to encourage bushier shrubs, more flowers, and to reduce size. Use caution around children and pets, as all parts of oleanders are highly poisonous; plant sap causes skin irritation to some individuals.

Most oleanders are vigorous growers and grow equally well in containers. In northern areas oleander is treated as a winter house plant; repot plant(s) in fresh media (soil) and set into a larger container. Overwinter this frost-tender plant by bringing it indoors when fall temperatures drop below 45°F at night. Some varieties are hardier than others. Prune plant back hard before bringing into a sunny room for the winter.

Aphids and scale are occasional nuisance pests and oleanders are deer resistant.

‘PeeDee Ingot’ Liriope Brightens Dark Areas

Posted by Hugh on July 6th, 2015

Liriope muscari ‘PeeDee Ingot’ (full sun)

Liriope muscari ‘PeeDee Ingot’ (part shade)

If you live in the Southeastern U.S., another variety of liriope probably will not impress you. Here we call it “monkeygrass”. PeeDee Ingot liriope (Liriope muscari ‘PeeDee Ingot’) is no ordinary ground cover (USDA hardiness zones 6-10). ‘Peedee Ingot’ liriope is named after the Peedee River in South Carolina near where it was found.

You might mistake it for Ogon sweetflag (Acorus gramineus ‘Ogon’) for its gold colored foliage. Liriope’s lilac-lavender flower spikes in mid-summer should convince you otherwise. Individual clumps grow a bit more than 18 inches tall and almost twice that in width.

The spikes of lilac-lavender flower provides a wide contrast against the grass-like chartreuse leaf blades. Plant it in average well-drained soils and in partial to full sun for best expression of its gold color. PeeDee Ingot needs some respite in summers south of zone 7. Its gold color will likely fade away or burn leaf tips if sunlight is too bright and the ground too dry.

Annual growth rate is not as rapid as many green leaf liriopes. This long-lived perennial is easy to grow with few disease and pest problems. PeeDee Ingot tolerates heavy shade, but most of its golden hue fades away by late summer. Clumps can be dug and divided almost any time they’re actively growing.

PeeDee Ingot is commonly used as a ground cover, utilized for front bed edging in the garden or container. It serves as a beautiful foil among other nearby plants with green or purple foliage colors.

Like most liriopes, the evergreen foliage maintains its presence through the winter, although abit bedraggled by winter’s end. Now is the time for a drastic crew cut to freshen foliage that will be emerging shortly. Pruning (mowing down) clumps is done at the start of spring.

My Search Continues For A Hardy Gardenia

Posted by Hugh on July 3rd, 2015

Gaardenia As Hedge Plant At Fast Food Restaurant in NC

Gardenia As Hedge At Fast Food Restaurant in NC

Non-hardy Double Flowered Gardenia in Tree Form

The longer you garden, many plant species keep improving, including their winter hardiness. A few years ago, growing gardenias (Gardenia jasminoides) in a U.S. zone 6 garden was a dream. Today, hardy gardenias are a safe bet in zone 7 or in zone 6 in a protected area of the garden, away from wintry winds. Otherwise, gardenias make good houseplants.

Pure white fragrant flowers cover this lovely evergreen shrub in early summer. Single pinwheel shaped flowers are most common, but semi-double and double flowering types are also available. Cultivars vary in flower fragrance from a hint to highly scented.

Gardenias grow 2 – 6 feet tall and 3 – 6 feet wide, depending on cultivar and desired size after pruning. Gardenia care is similar to that of rhododendron or camellia. Provide morning sun and afternoon shade or in full day dappled sunlight. Locate gardenias near a home entry door, patio or deck, where you and your guests may fully enjoy their fragrance.

Whether planted in a container or garden bed, gardenias require moist, well-drained, acidic medium (soil) that contains lots of organic matter. Gardenias need watering when rainfall is less than an inch per week. Fertilize plant(s) every spring with an acidic type fertilizer such as water-soluble Miracle-Gro™ or Espoma Hollytone™.

Yellowing leaves indicates any of three possible problems. If it is the bottom foliage turning yellow, it could be under- or over-watering. If the upper leaves show interveinal chlorosis (yellowing), your gardenia plant needs an iron supplement or the soil is not be acidic enough. Gardenias are subject to a number of pests which can be managed using insecticidal soap.

‘Frost Proof’ and ‘Daisy’ are two that I have trialed in my zone 6 garden. The harsh winter of 2013-14 killed both varieties to the ground. By late June both cultivars had sprung back to life from the crown but did not bloom. A year later both cultivars were dead.

Hummingbird Favorite Plants

Posted by Hugh on July 1st, 2015

Salvia elegans favorite hummingbird plant

Salvia splendens favorite hummingbird plant

Albizia julibrissin is hummingbird magnet, potentially invasive in some areas

Many lists of hummingbird plants available in books, on the internet, and at garden centers aren’t very good hummer plants (e.g. petunias, daylillies). Inclusion of whole genera (e.g. Penstemon or Aquilegia) is not correct as only a few species supply ample quality nectar to hummingbirds.

Creating a definitive list of the best hummingbird plants is nearly impossible as hummer species have different taste buds regionally. Note that preferred flowers are tubular shaped and bloom in the summer. In addition, North American native plants are more to their liking than Asian or European species. Warning: some plant genera may be potentially invasive.

There are 115 genera and 330 species of hummingbirds worldwide. However, fewer than two dozen species spend summers in the U.S. and Canada, and very few species remain year-round. Most spend winters in Central America or Mexico and migrate north to their breeding grounds in the southern and western U.S. as early as February, and to areas further north later in the spring.

Perennials

Native Columbine (Aquilegia canadensis)
Coral Bells (Heuchera sanguinea) – fancy-foliaged cultivars provide less nectar
Red Beardtongue (Penstemon barbatus)
Bee Balm (Monarda didyma)
Cardinal Flower (Lobelia cardinalis)
Hollyhock (Alcea)
Delphinium

Annuals—some are perennials in southern climes where they are and bloom in the summer and early fall.

Salvia –several species such as Pineapple Sage (Salvia elegans), Scarlet sage (S. coccinea) or (S. splendens), Anise sage (S. guaranitica), Autumn sage (S. greggii)
Flowering Tobacco (Nicotiana) – some, but not all attract hummers.
Canna (Canna indica) – short growing, small red flowers.

Vines—many good options here, both woody perennial vines and annuals

Crossvine (Bignonia capreolata)
Coral Honeysuckle (Lonicera sempervirens)
Trumpet Creeper (Campsis radicans) – Hybrid and Asian cultivars not as attractive to hummers.
Annual vines – Spanish Flag (Mina lobata) and Cardinal vine (Ipomoea x multifida)

Trees/Shrubs

Red horsechestnut (Aesculus pavia)
Silk Tree (Albisia julibrissin)
Butterfly bush (Buddleia)
Catawba Rhododendron (Rhododendron catawbiense)
Rose of Sharon (Hibiscus syriacus)
Weigela (W. florida)
Asian honeysuckles (Lonicera)
Lilacs (Syringa spp.) – select brightly colored

Delightful Dragonflies And Damselflies

Posted by Hugh on June 27th, 2015

Dragonfly (Photo by Dr. Frank Hale, UT Entomologist, Nashville)

Damselfly (Photo from Dr. Frank Hale, UT Entomologist, Nashville, TN)

Watch them flitter… Dragonflies and damselflies, also called “darning needles” and “dining needles”, are common spring/summer inhabitants in many U.S. gardens, particularly around water gardens, streams and other water features, where they reproduce. Adults lay eggs on the plants around the water’s edge; the nymphs hatch from the eggs and live under water for months or years before they mature and fly. These insects are in the order Odonata.

Dragonflies and damselflies are beneficial insects and delightful to watch. Young children enjoy seeing them flit around reeds, lilypads, and flowers; children frequently cause panic when they fly to close. However, they do not sting or bite people. Dragonflies and damselflies are predators of other insects, including mosquitoes and beetles. They have excellent eyesight and are fast nimble fliers.

Both dragonflies and damselflies tend to stay close to where they were born. Key differences between them is that dragonflies rest with their wings held open; damselflies fold their wings back over their abdomens while resting. Some people refer to dragonfly nymphs (immatures) as “skimmers”.

Dragonflies live around water ponds and features, such as a large urn or half whiskey barrel filled with water. Dragonflies are most active on warm spring and summer days. They prefer ponds with plants growing in or around it where the nymphs can hide and hunt. Young fliers will rest (bask) on rocks and twiggy shrubs; tall cattails, reeds and grasses are great places to perch on.

Dragonflies and damselflies are an important food source for various birds. Pond fish or frogs will prey on the nymphs.

Credit: idea for blog originates from writings of Rick Darke and Doug Tallamy whose books on garden ecology should be general reading for children and adults.

Persian Shield Offers Radiant Foliage Color

Posted by Hugh on June 24th, 2015

Persian shield and coleus at Biltmore Estate, Asheville, NC

The iridescent purple foliage of Persian shield (Strobilanthes dyerianus) radiates in a warm summer garden in the U.S. Here it is treated as an annual (USDA hardiness zones 9-11). Persian shield is native to tropical Myanmar (formerly Burma), where it is a 3-4 feet tall soft-stemmed evergreen shrub or subshrub. In temperate regions it grows only 1-3 feet.

Dark green leaves (to 8 inches long) are flushed with silvery-purple variegation above and dark purplish tints beneath. In the tropics, tiny violet 5-lobed flowers appear in short cone-shaped inflorescences. It rarely blooms in non-hardy regions.

Persian shield prefers compost-rich, moist and fertile soil. Two keys to successfully growing Persian shield are light exposure and plentiful soil moisture. Depending where you garden, plant in full sun or partial sun or moderate shade. It thrives in the heat and humidity of the southeastern U.S. In cooler areas (zones 4-6), full day sunlight is ideal. Where summer temperatures sizzle, a few hours of early morning sunlight is adequate. Partial shade brings out the deepest purple in the leaves.

From spring through summer Persian shield plant responds to constant feeding. Fertilize it with a water soluble products such as Miracle-Gro™, Nature’s Source™, or Daniels™ at half rate and twice as often (contrary to package directions) to maximize shoot growth and not to burn the roots.

Pinch stems every few weeks to develop a compact, bushy plant. Use the pinched cuttings to start new plants (see below). Otherwise, Persian shield will develop a 3 feet stem, that will likely need staking to prevent flop over. Persian shield has few, if any diseases and pest problems. Occasionally, spider mites may discolor the leaves.

In the fall, with killing frost pending, take cuttings from garden plants and grow them as house plants over winter. Cuttings easily root within 3 weeks in moist sand and/or vermiculite and held in a plastic tent for high humidity. Provide moderate light, but not direct sunlight, so as not to burn the tender unrooted cuttings. Transplant into good potting soil and keep adequately watered and fertilized until mid to late spring.

Obedient Plant For Late Summer Blooming

Posted by Hugh on June 21st, 2015

Late Summer Blooming Obedient Plant

Obedient plant (Physostegia virginiana) is native from the Central to Southern U.S. and northern Mexico (USDA hardiness zones 3-9). It is called “obedient plant” because each tubular flower will, upon being pushed in any one direction, stays in new position.

From July to September obedient plant is valued for its late season pink or white flowers. Tubular, two-lipped pink flowers in upright terminal spikes (each to 12-18 inches high) bloom throughout summer atop stems rising to 3-4 feet high and 1-2 feet wide. Flowers attract numerous pollinating insects.

Obedient plant tends to seed-in and also spreads prolifically by rhizomes. The leading cultivar is a non-spreading form appropriately named ‘Miss Manners’; it grows more tidy and is better behaved; its snapdragon-like flowers are pure white. It selected by Darrell Probst of Garden Visions in Hubbardston, MA. Miss Manners is a shorter grower, 18 inches high and 12 inches wide. It has a clumping habit, good secondary branching, and will rebloom when deadheaded. Foliage is deep green, glossy foliage.

Obedient plants grow best in average well-drained soil and in full sun. Plants growing in light shade or in rich, highly fertilized soils tend to flop and need staking. Prune back plants by half in late spring to improve branching and minimize possibility of floppiness. Plants should be divided every 2-3 years to keep beds neat.

It has no serious disease or pest problems and deer generally avoid it. In wet summers rust disease may be troublesome. Obedient plant naturalizes freely and eventually becomes overcrowded in a wildflower or meadow garden. It may be sited in rain gardens as plant tolerates temporary flooding. Flowers are a welcome addition in floral arrangements because flowers obediently hold in almost any position you desire.