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

Fifteen Garden Perennials Which You Can’t Kill (Or Almost)

Posted by Hugh on February 26th, 2018

Herbaceous peony

Daylily

Here is a list of flowering perennials that need little care after planting. Ornamental grasses and ferns are not listed here. One steadfast rule that you must follow if this group of plants are to work for you: “choose the right plant for the right site”. Shady plants in full sun and terrestrial plants in swampy ground are no-nos. If these plants are properly planted, all should prosper.

In most locations (zones 5-7), they’re long-lived and are disease and insect free. Many (except where indicated) flowering perennials prefer full sun and humus-rich well-drained soil.

The list:

Italian arum (Arum italicum) – bright variegated foliage arise in fall and grow through winter; red cluster berry fruits appearing in late spring; partial to full shade.

Baptisia or wild indigo (Baptisia spp.) – full sun; purple, blue, yellow or white flowers appear in mid-spring.

Coreopsis (Coreopsis spp.) – full sun and moderate soil moisture; many cultivars including single-, semi-, or double- petalled yellow flowers bloom in late spring thru summer if deadheaded.

Lenten rose (Helleborus x hybrida) – many great cultivars to choose from; partial shade; mid-to late winter flowering.

Catmint (Nepeta x faassenii) – several great cultivars including ‘Walker’s Low’ and ‘Six Hills Giant’; spring-summer flowering.

Cranesbill, hardy geranium (Geranium spp.) – lots of great cultivar choices available; partial shade; spring flowering, popular cultivar ‘Rozanne’ blooms intermittently from late spring to autumn.

Chinese astilbe (Astilbe chinensis) – many cultivars; easier to grow compared to A. x arendsii; morning sun; late spring-early summer blooming.

Fairy Wings, barrenworts (Epimedium spp) – excellent ground cover ; early spring flowers; deciduous or evergreen varieties available; partial to full shade.

Siberian iris (Iris sibirica) – green, black and variegated foliage and numerous flower colors; full sun.

Daylilies (Hemerocallis x) – over 70.00 varieties to choose from. Select those suited to your regional location; shop at a daylily grower in your locale.

Peony (Paeonia officinalis) – hundreds of great cultivar choices available; full to partial sun; mid-spring flowering.

Russian sage (Perovskia atriplicifolia) – full sun; mid-summer and later bloomer; several new dwarf or compact growing cultivars such as ‘Denim and Lace’, ‘Little Spire’, ‘Filigran’.

Variegated Solomon seal (Polygonatum odoratum ‘Variegatum’) – bright variegated foliage, flowering is secondary; partial shade.

Tall sedums (Sedum x spectabile) – several cultivars; full sun; summer flowering.

Lilytuft, Monkeygrass (Liriope muscari) – part to full sun; many cultivars including with dark green ‘Big Blue’, striped ‘Variegata), and chartreuse (‘Peedee Ingot’); clumps 8-12 inches high; Spike-like clusters of pale violet to white flowers in mid to late summer.

Understanding How To Purchase Nursery Stock

Posted by Hugh on February 23rd, 2018

Large b&b Tree ready for shipping

Covered nursery stock ready for shipping

Nursery growers supply trees and shrubs to garden centers in any of five ways:

Container Grown – Plants have been growing in a container or pot for one or more growing years. Some plants have been grown in containers or they were field dug and repotted into containers. These transplants are not likely to experience transplant shock. Before planting, take a few minutes to “tease” the outer roots, particularly if they are pot bound or over crowded.

Field Dug To Containers – Many plants are dug out and placed into pots to be put on display for sale at the nurseries. When dug out, they are either dug with soil or moved bare-root. The question is: how long have they been growing in the pot since being moved from the field; six months or a year is ideal, but sometimes it may be one month or less. Many are potted in spring and then immediately shipped to the store. Often the roots have not acclimated to the new soil or the root balls have been damaged. Essentially you are buying a bare-root transplant, potting mix and the container. Some nurseries have “root pruned” the plant to fit into its new container size.

Balled And Burlapped (b&b)- The tree or shrub is dug from the field by hand or by a tree digger (laborer) along with the soil. The root ball is wrapped in burlap and jute (never nylon) twine. Many of the fine feeder roots are lost in digging. A b&b tree will usually survive transplanting if purchased and planted in late winter thru mid-spring. The tree may still be susceptible to transplant shock. Obtain a one-year money-back guarantee from the nursery or garden center.

Bare Root – Some trees and shrubs can be successfully transplanted without any soil on the roots. The trees are fully dormant, either in late fall or very early spring. In early spring roses, fruit trees, raspberries, grapes, and blueberries are sold this way. Once the leaf buds have emerged in spring, the chances of a successful transplant quickly falls off. Bare root plants should be planted immediately into your landscape. When these plants are on sale in late April and May, it’s best to pass them up. Obtain a money-back guarantee from the nursery or garden center selling bare root plants.

Machine-Dug – Professional landscapers dig and move large trees from a nursery field or private property with a mechanical tree spade to a new planting site. The success of this technique is fully dependent on how much of the root ball can be moved intact. Larger nursery grown trees experience severe transplant shock.

Select A Good Street Or Landscape Tree

Posted by Hugh on February 20th, 2018

‘Happidaze’ sweetgum on Median Strip In Johnson City, TN

‘Sango Kaku’ Japanese maple for sale at Samara Farms Nursery near Nashville, TN

First of all, there is no perfect tree, either for a street or landscape planting. However, many excellent cultivars are now available at local nurseries and retail garden centers. Select one that matches your site requirements. Site factors include: amount of sunlight daily, soil type, soil pH (acidity or alkalinity), and soil drainage.

What kind of tree do you want -shade, flowering, privacy? Will it fit size-wise into the landscape? Avoid fast growing trees like silver maples (Acer saccharinum), Siberian elms (Ulmus pumila), cottonwoods and poplars (Populus spp.), walnuts (Juglans spp.), and willows (Salix spp.) that are susceptible to storm damage and are short-lived. They may also be hosts to insect and diseases and drop messy fruits or seeds. Does the site have height limitations (look up for power lines) and enough for root growth. Are roots shallow such as maples, some oak species, or elms which may uplift sidewalks in a few years.

A good shade or street tree is a long-term investment. Start by purchasing a high-quality plant. Trees 8 to 10 feet tall, either balled and burlapped (B&B) or growing in containers, are usually the best buy. Species that are difficult to transplant may be more easily to establish if you start with a smaller size. The tree may even come with a guarantee with free replacement.

Where to find good reliable information regarding the best tree to plant? Check at your local Extension office or land grant university. They will usually list the most reliable tree for your region. Many independent garden centers stock these recommended cultivars. Additionally, search for plant sales at a local botanical garden and arboretum.

Trees are listed in three size groups according their size. Large trees reach a mature height greater than 60 feet. Medium-sized trees grow to 30 and 60 feet. Small trees (less than 30 feet tall) may be also classified as flowering or ornamental trees such as crape myrtles, redbuds, crabapples, dogwoods (Cornus spp.), and Japanese maples; over the years they mature into a handsome small shade tree.

Winter Blooming Winter Jessamine

Posted by Hugh on February 17th, 2018

Gelsemium sempervirens ‘Butterscotch’ at Atlanta Botanical Garden

Bright yellow tubular flowers of jessamine

Carolina jessamine (Gelsemium sempervirens) is one of the most beautiful native vines in the South (USDA Zones 6 to 9). In February and March, its bright yellow flowers are commonly seen growing along roadsides in the Southeastern U.S. It is frequently mistaken for forsythias a shrub that rarely blooms in winter.

Vines grow vigorously, 20 feet or more if not pruned. Gardeners may choose to rein a jessamine into a 3-4 foot tall shrubby vine covering only 3-5 square feet of ground. Its annual growth rate is 12-15 inches in average soil and no irrigation and a lot more aggressively in rich soil and adequate watering.

From February to April, sweetly scented golden yellow flowers blanket the cascading, fine textured foliage. The tubular 1 to 1½ inches long blooms are 5 lobed. Flowers invite early arriving butterflies and bumblebees into your garden. Glossy 1 to 3 inches long leaves are evergreen.

Carolina jessamine is easy to grow. Plant it on a trellis (arbor), in a container on a deck and patio or as a ground cover along steep banks erosion control.

Carolina jessamine tolerates either full to partial sunlight. Flowering is more prolific and foliage is denser in full sun. Moist well-drained soil is ideal. Jessamine can withstand periods of drought once established after one year. Ground cover plants should be spaced 3 feet and 5- 8 feet apart as a trellis.

Fertilize while the plant is actively growing with moderate amounts of a slow-release fertilizer such as Osmocote™ or Nutricote™. Do not over-fertilize as it may reduce flowering.

In containers jessamine may require pruning 2-3 times annually to hold growth in check. Many gardeners utilize a string pruner for this task. Old, sickly or out of control vines can be pruned back to a few feet above ground level after flowering. Remove all dead or broken branches.

Popular Cultivars:

‘Pride of Augusta’ – popular double-flowered cultivar with long bloom period; also listed as ‘Plena’.

‘Margarita’ – slightly larger flowers and is rated cold hardier than species.

‘Woodlander’s Pale Yellow’ – large creamy-yellow but is rated as not as cold hardy (Zone 8 -10).

Butterscotch™ – blooms 2 to 3 weeks later than species and often re-blooms in fall.

Lemon Drop™ – more compact with shrub-like habit and with light yellow flowers.

All parts of the plant are highly poisonous. The sap may cause skin irritation. Insects or diseases are rarely a problem on Carolina jessamine. Deer and rabbits will not eat it. Carolina jessamine is the state flower of South Carolina.

Seven Step Care Tips For Container Roses

Posted by Hugh on February 14th, 2018

Highlt Rated ‘Flower Carpet Pink’ Rose

‘Doris Day’ floribunda

You can grow beautiful roses in containers on your patio or deck. All you need is an adequate container size and a growing area with plenty of sunlight. The life of container roses is short,usually 2-3 years. Each spring, plants should be transplanted every year into a new container. Container size is very important. Follow these 7 steps:

Choose the right rose. Fragrant, compact, disease-resistant varieties with continuous blooming perform best. Smaller rose types- miniature, floribunda, and some hybrid teas work the best. Compact Flower Carpet™ roses are an excellent size for small containers for 3-5 gallon containers. Also try the Carefree™, Oso-Easy™, and Home Run™ series.
Pick the right pot. Anything with a drainage hole(s) will work. It should be deep enough as roses have long, deep root systems; aim for a depth and diameter of 15 inches or more. 1/2 barrels are a great choice.
Plant into a quality potting mix and enrich with compost to increase water holding capacity.
Water containers regularly so that media (soil) stays moist, but not sopping wet. If your rose container dries out in less than two days, it may be potbound or the container is too small to support its roots.
Feed every 4 to 6 weeks with a water soluble fertilizer such as Miracle-Gro™ or Jacks™ for more blooms. In colder zones, stop fertilizing 8 weeks prior to first frost. Add 1-2 teaspoons of Epsom salt (Magnesium sulfate) 2-3 times during the growing season.
Keep your rose(s) pruned: (a) deadhead, (b) size and shape, and (c) control insects and disease.
Re-pot every 1-2 years to refresh the soil. Transplant into a larger container if you observe a decrease in blooms.

Warning: thin plastic and clay pots may crack during freezing winters. In northern regions (Zones 3-6), winter protection of the tender roots is an absolute must.

Get An Early Start On Spring With Dawn Viburnum

Posted by Hugh on February 10th, 2018

Viburnum bodnantense ‘Dawn’ at NC Arboretum in Asheville, NC

Summer foliage (labelled ‘Pink Dawn’)

Viburnum x bodnantense (cross between V. farreri and V. grandiflorum) is a hybrid viburnum that was developed at Bodnant Garden in Wales in 1934-1935 (USDA zones 5-9). Also called Pink Dawn, this shrub is cherished for exceptional three-season interest – fragrant pink flowers in spring, clean, blemish-free summer foliage, and above average fall color.

‘Dawn’ is a cultivar that features rosy-pink flowers. The shrub grows upright in a multi-stemmed, vase shaped habit. It typically matures to 8-10 feet tall and 4-6 feet wide. Toothed, 2-4 inch long narrow-ovate leaves emerge in spring with bronze tints on leaf edges; leaves mature to deep green hues. Foliage turns an attractive burgundy-red in fall. Flowers give way to red berries (drupes) that ripen to black in the fall.

Its showy flowering habit is reason enough to plant this early flowering viburnum, in many years blooming alongside winter-flowering winterhazels (Corylopsis), fragrant honeysuckle (Lonicera fragrantissima) and paperbush (Edgeworthia). In zone 6, the reddish buds swell and open into the clusters of long-lasting, clear pink, tubular flowers. Summer foliage is dark green and branches are cinnamon colored.

Dawn viburnum grows in average, medium moisture, well-drained, moderately acidic soil in full sun to partial shade. Expect greater numbers of flowers in full sun and less so in shady landscape areas. Avoid soils that are droughty or soppy wet. Site the shrub in a protected location to help protect spring flowers to hard freezes. Fertilize and mulch shrub(s) in early spring. Prune the shrub immediately after spring flowering is over.

Dawn viburnum may be planted as a foundation or plant several for a hedge or privacy screen. Cultivar named ‘Charles Lamont’ grows 1-2 feet taller but is not as wide. All other traits similar to ‘Dawn’.

Habit is upright-spreading with stiff, coarse branching. Grows 10-12′ tall and about 2/3 as wide. Flowers are slightly larger and a brighter pink than ‘Dawn’ and have yellow anthers. Flowers at a very young age and thought to be more free flowering. The leaves are also larger than that of ‘Dawn’.

No serious insect or disease problems trouble this shrub viburnum. Late winter/early spring flowers are susceptible to frost damage.

Dawn viburnum has received the Royal Horticultural Society Award Of Merit.

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.