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

August Is Also An Important Planting Month

Posted by Hugh on August 1st, 2016

Cabbages heading at Dallas Arboretum in early January

‘Wirosa Savoy’ Cabbage at Atlanta Botanical Garden in October

“A” starts the alphabet. To most gardeners April starts out the spring planting season. Temperatures are in the comfortable 70°F degree range. Four months later in August, temperatures outside are sweltering. Many of us call them the hot humid “dog days” of August. Dogs and gardeners are suffering alike.

However, August is also a great time to plant flowers and vegetables. Visit the local garden center and buy large 6 inch size annuals which are often “on sale”. Buy fresh plants and not the potbound, worn out leftover annuals which the store did not sell in the spring. Some of the best to plant in August include petunias, calibrachoas, (million bells), geraniums, snapdragons, diascias, and marigolds. Pansy seed must be started in a cool basement environment under “gro-lights”.

In the mid-South region (USDA hardiness zones 6 and 7), September and October weather is usually great for flowers planted in mid-summer. When setting out plants, water them daily during week one, then every 2-3 days in the 2nd and 3rd weeks. Then, water plants as needed. These annuals are demonstrate exceptional cold tolerance, unfazed by mid-20°F nights in fall.

Many vegetables may be established in August. Cabbage, broccoli, cauliflower, lettuce, carrots, beets, and green beans need 60-70 days above freezing to produce a good crop. Cole crops such as broccoli, cauliflower, brussel sprouts, and cabbage are easiest to produce in the late summer into autumn than those started in spring. Spring plants often bolt (go to seed) in the spring as temperatures heat up. Cole crops welcome the cool days of autumn.

In addition, pest activity diminishes with cooler temps. Some pesticide spraying may be needed, although plants can be protected with a cheesecloth or Remay fabric cover. Use a safe bio-insecticide like Dipel or Bt (Bacillus thuringiensis kurstaki) against wormy caterpillar pests.

Chanticleer Garden – A Garden For Ideas

Posted by Hugh on July 30th, 2016

Fall Scene at Chanticleer

Tropicals In Terrace Gardens

Chanticleer Garden is an estate and botanical gardens, that bills itself as a “pleasure garden”. Chanticleer is “a garden for ideas”. The property is located at 786 Church Road in Wayne Pennsylvania, approximately 30 minutes of Philadelphia. Chanticleer celebrated its 100 year centennial in 2013 as the Rosengarten estate and 20th year as a public garden. The entrance gate is crested with carved stone roosters (chanticleers in French). The house and grounds have been listed on the National Register of Historic Places since 1984.

Chanticleer is a destination garden to enjoy, learn, and relax. Gather lots of ideas to take home to your property. The garden has evolved greatly since the death of the owner in 1990. As the home of the Rosengartens, Chanticleer is green and beautiful with impressive trees and lawns. Most of the floral and garden development you see today has occurred since 1990, designed by Chanticleer staff and consultants.

Seven horticulturists are assigned to the seven areas of the garden; they design, plant, and maintain their garden area. The Teacup Garden and Chanticleer Terraces feature seasonal plants and bold-textured tropical and subtropical plants. The latter areas change greatly from year to year. In the fall non-hardy plants are dug up and overwintered in greenhouses and basements.

The Tennis Court, Ruin, Gravel Garden, and Pond Garden focus on hardy perennials. The Tennis Court is a floral and foliar delight. The Ruin is a folly, built on the foundation of Adolph Rosengarten, Jr.’s home. It is meant to look as if the house fell into disrepair. The Gravel Garden is hot and dry, a touch of the Mediterranean in Pennsylvania. The Pond area is nothing short of a floral masterpiece.

Asian Woods and Bell’s Woodland are shady areas that feature native plants of eastern Asia and eastern North America. The cut flower and vegetable gardens produce flowers for arrangements and food for the restaurant and staff tables. Surplus goes to a local shelter.

Chanticleer gardeners will answer your questions about our 5,000+ plants. Plant lists and photographs are posted in on-site handmade mailboxes. The information is also available online.

The Chanticleer Foundation owns 47 acres, 35 of which are now open to the public. The main walking path is just under a mile long. Relax, read, sketch, converse, meditate. Picnic tables, benches and Adirondack chairs are spotted around the property for leisure and to catch views of plants and wildlife.

Chanticleer is open Wednesday through Sunday, April through October, from 10 a.m.to 5 p.m. Admission fee: $10 (2014). Plan a minimum 2-3 hour visit.

Woodland Respite

Need To Deadhead Perennials

Posted by Hugh on July 28th, 2016

Veronica ‘Royal Candles’

Blanket flower (Gaillardia) re-blooms after deadheading

Deadheading is the practice of removing spent blossoms to stimulate re-blooming. It also refreshes the plant’s appearance, and lessens the threat of seed dispersal. It redirects the plant’s energy from seed production to root and shoot growth.

Deadheading is an extra chore throughout the growing season. When the plant (perennial or annual) has stopped blooming or its appearance starts to decline, remove the entire flower stalk. Depending on species, a perennial may bloom again 2 -3 more times. Weather and soil moisture and soil fertility are also key factors.

After deadheading apply a water-soluble fertilizer such as Miracle-Gro™ or Schultz™. This is good time to clean up the bed, weed, and add organic mulch. If the soil is dry, irrigate the bed deeply with 3 – 4 hours of overhead irrigation (equivalent of 1 ½ inches of rainfall).

Many perennials do not respond to deadheading. Like other types of pruning, deadheading is plant species specific. It can be difficult to group plants (or people) into categories. For most plants remove spent flowers and stems back where they originate near the plant base. New lateral shoots should appear within a few weeks and blooms 3-5 weeks later.

Deadheading Some Perennials (this list is not complete):

These popular perennials respond to deadheading:

Yarrow (Achillea spp.)

Hollyhock (Alcea rosea)

Columbine (Aquilegia spp.)

Butterfly weed (Asclepias tuberosa)

Hardy begonia (Begonia grandis)

Canna lily (Canna spp.)

Tickseed (Coreopsis spp.)

Cheddar pink (Dianthus gratianopolitanus)

Delphinium (Delphinium spp.)

Foxglove (Digitalis spp. and cvs.)

Purple coneflower (Echinacea purpurea)

Blanket flower (Gaillardia x grandiflora)

Gaura (Gaura lindheimeri)

Geum (Geum spp.)

Sneezeweed (Helenium autumnale)

False sunflower (Heliopsis helianthoides)

Lavender (Lavandula spp.)

Shasta daisy (Leucanthemum x superbum)

Lupine (Lupinus spp.)

Bee balm (Monarda spp.)

Penstemon (Penstemon barbatus)

Garden phlox (Phlox paniculata)

Perennial salvia (Salvia nemorosa)

Pincushion flower (Scabiosa spp.)

Indian pink (Spigelia marilandica)

Stokes’ aster (Stokesia laevis)

Spiderwort (Tradescantia x andersoniana)

Spike speedwells (Veronica spicata)

Culver’s root (Veronicastrum virginicum)

Time to deadhead Helenium

Long-Blooming Tennessee Coneflower

Posted by Hugh on July 24th, 2016

Echinacea tennessiensis

TN coneflower at Butterfly Arboretum in Jonesborough, TN

Native to a two-county area of mid-Tennessee, Tennessee coneflower (Echinacea tennessiensis) is a popular favorite among gardeners across the U.S. because of its long blooming season. It has also spawned a few hybrid selections. The pale pink, flat-topped flowers with green and burgundy centers (cones) follow the tract of the sun across the sky.

From July thru September Tennessee coneflower has short, slightly upturned petals that are 2 to 3 inch across. Petals are not reflexed backwards as those of purple coneflower (E. purpureum).

Tennessee coneflower prefers moist well-drained soils until well-established. It is an ideal choice for hot sites and in rocky shallow soils. The species is best suited in full sun, but can cope with partial shade.

Tennessee coneflowers have no serious insect or disease problems. Japanese beetle, powdery mildew and leaf spot are occasional problems. They do not benefit from additional fertility which may actually weaken stems. Flowers attract many species of birds and butterflies. Deer do not normally feed on coneflowers.

Divide clumps when they become overcrowded every 4 to 5 years. Plants re-bloom without deadheading. Prompt removal of spent flowers improves general appearance. Group several plants together in a perennial border, meadow, or wildflower garden. Compact forms grow well in containers for a long bloom season.

Hybrid cultivars:

‘Rocky Top’ is a compost grower with pastel pink on 2 to 3 feet tall and 1 foot wide plants.

Pixie Meadowbrite™ is another compact form medium pink flowers. A true dwarf, each plant grows to 18 inches tall and 20 to 24 inches wide.

Once listed as endangered, Tennessee coneflower has now been de-listed and is easy to find in commerce.

Spider Flowers Excel In Summer’s Heat And Humidity

Posted by Hugh on July 21st, 2016

Spider flower (Cleome) at Dallas Arboretum in Texas

Cleome ‘Senorita Mi Amor’ at Univ. of Tennessee Gardens, Knoxville, TN

Spider flowers (Cleome x hybrida) are top performing summer flowering annuals. Each year plant breeders introduce compact varieties to beautify flower beds and container gardens. Select among vegetative and seed produced types.

Spider flowers ask for weekly watering and full day sunlight (best) to achieve maximum blooming potential. They will grow in a partially shaded beds but bloom less and the plants tend to stretch.

Cleomes grow in average soil that is well-drained. Amending the soil with compost at planting and mulching are highly recommended to keep them highly floriferous. Rated as moderately drought tolerant, spider flowers prosper under weekly irrigation. Before planting work in lots of compost into garden soil or container media; broadcast a slow release fertilizer over the entire bed.

By mid-summer heavy feeding plants, particularly those in containers, become nutritionally deficient. Bottom leaves are first to turn yellow and bloom count becomes more sparse. Summer- feed container plants twice monthly with a water soluble fertilizer such as Miracle-Gro®, Peters®, or Schultz® at label rates.

Spider flowers are highly disease and pest resistant. Low compact forms require no staking compared to old-fashioned tall varieties that your grandmother used to grow.

Leading Cleome hybrids are:

Cleome Clio Magenta – 18 – 36 inches tall and 12 – 24 inches spread violet spider-like flowers with pink overtones.

Senorita Rosalita – 24 – 48 inches tall and 18 – 24 inches wide; do not self seed, keeps its lower foliage all season long; not prickly.

Sparkler series -reach 3 1/2 – 4 feet tall; plants are vigorous, and bloom heavily from spring to early fall; choice of white, blush and lavender.

Do Not Call Them “Weeds” Any Longer

Posted by Hugh on July 18th, 2016

‘Gateway’ Joe Pye in East Tennessee Garden

Helenium ‘Moerheim Beauty’

Butterfly weed (Asclepias)

Some plants deserve more respect. Over the years several U.S. native species have been tamed or domesticated. Yet, they retain their common name “weed”. Four popular former “weeds” are:

butterfly weed (Asclepias tuberosa)
ironweed (Vernonia lettermannii ‘Iron Butterfly’),
sneezeweed (Helenium autumnale), and
Joe-Pye weed (Eupatorium spp.).

Butterfly weed (Asclepias tuberosa) is a tuberous rooted long-lived perennial found in dry/rocky open woods, glades, prairies, fields and roadsides across the Eastern and Southern U.S. Plants are slow to establish and may take 2-3 years to produce flowers. Mature plants may freely self-seed in the landscape if seed pods are not removed prior to splitting open. Butterfly weed does not transplant well due to its deep taproot, and is probably best left undisturbed. It typically grows in a clump to 1-3 feet tall and features clusters (umbels) of bright orange to yellow-orange flowers atop upright to reclining, hairy stems with narrow, lance-shaped leaves.

Joe-Pye (Eupatorium spp.) has 4 to 5 feet select varieties which grow much shorter than the wild species. Sturdy stems are clothed with whorls of green leaves and topped with dome-shaped heads of lavender to pink flowers in mid-summer . Leading cultivars are: ‘Gateway’ -tiny, dusky rose-pink flowers form a huge, terminal, domed, compound inflorescence (12-18 inch diameter) in mid-summer to early fall, ‘Chocolate’, and ‘Little Joe’.

Ironweed (Vernonia lettermannii) is a compact, well-branched and vigorous plant. In late summer its vivid purple flowers are covered with butterflies and other pollinators. Ironweed is found growing in poor rocky soils, tolerates long periods of submersion (flooding), yet it is highly tolerant of hot dry sites. Cultivar ‘Iron Butterfly’ is a low mounding perennial form with narrow fine textured foliage. Plants are 2-3 feet tall and equal in spread. Sturdy plants are strongly anchored by a sturdy taproot. Branch terminals are covered by small clusters of deep purple disc florets in late summer.

Sneezeweed (Helenium autumnale) is an erect, clump-forming perennial which typically grows 2-3 feet tall (sometimes to 4 feet) on sturdy stems. It has a lengthy bloom season from summer into to early fall. Daisy-like 2 inch wide flowers have wedge-shaped, coppery-red (or yellow) rays that are notched at the tip and prominent, dark dome-like center disks. Leading cultivars are ‘Moerheim Beauty’.

All four perennials are favorite nectar plant of bees and butterflies, particularly the Monarch butterfly larvae. They prefer sunny sites with average to dry soils. Grow in average, medium to wet, well-drained soil in full sun. Over-fertilization may force plants to grow too tall. Although not required, three species, not butterfly weed (Asclepias) may be cut back in early July (at least 6 weeks before normal flowering) to reduce plant height and encourage branching, thus increasing bloom count, healthier foliage, and less need for support. Remove spent flowers to stimulate additional bloom. Divide clumps every three years to maintain vigor. They are disease and pest resistant and is not bothered by deer or other herbivores.

Late Summer Planting of Vegetables

Posted by Hugh on July 15th, 2016

Two Varieties of Cabbage for the Late Summer Garden

Cauliflower seedlings for sale at local Garden Center

Mid to late summer is the second season for planting many (not all) kinds of vegetables and herbs in many parts of the U.S. There is still 3 months or more of great growing weather ahead to harvest veggies planted now. You’ll enjoy great harvests for the Thanksgiving and perhaps the Christmas/winter holiday table (USDA zones 5-7).

Start with leafy greens for salads or garnish such as lettuce, pak choi, chard, and parsley. Carrots, beets, peas, green onions, spinach, radish, and some brassicas (cabbage, broccoli, cauliflower, and turnips) are good picks for the fall garden. Long season veggies such as tomatoes, cucurbits (cucumber, pumpkins, squash, and others), and sweet corn are not included.

Diseases, insects, and weeds are less problems. Crops like cabbage, cauliflower, and broccoli can be store outdoors in the garden row through most of the winter without them going to seed (bolting) or developing a bitter taste. Pick them as you need them for the dinner table. Transplants of lettuce, cabbage, broccoli, cauliflower, and others are available at local garden centers starting in August, depending on locality.

In summer start seedlings in pots, flats, or other containers in the cool home basement under gro-lights or in an outdoor cold frame; or directly sow seeds directly into the garden in dappled sun or light shade, but not in direct sun.

Set your new veggie transplants in a moist garden or raised bed, preferably around twilight when it is cooling off. In the mid-South protect new transplant seedlings under row covers or shade cloth for several days to acclimate them to sun and heat. Light sprinkling (spritzing) seedlings 2-3 times daily also cools seedlings.

Seedlings should adapt to outdoor beds within a week. Keep them adequately watered and fertilized. In USDA zones 8, 9, and 10, some fall-planted crops are harvested all winter long.

Comparing Oriental Lilies To Asiatic Lilies

Posted by Hugh on July 13th, 2016

‘Black Beauty’ Orienpet Hybrid Lily

Asiatic Hybrid Lily

Both Asiatic and Oriental lilies (Lilium spp.) are popular lilies in U.S. gardens. Hybrid cultivars share traits of both species. Lilies grow in a wide variety of soil types and are not pH sensitive. They flower in full to part partial sun (5 hours minimum of sunlight). Both prefer a well-drained soil and mulch to keep roots moist and cool.

Both Oriental and Asiatic lilies are top-notch garden performers. Oriental lilies enjoy cooler summer temperatures and are best planted in afternoon shade or all-day dappled sunlight in hotter climates. In mild climate summers, where the average temperature doesn’t usually exceed 90 degrees during July and August, Oriental lilies do equally well in full sun or light shade. No winter mulch is required if your climate is warmer than USDA hardiness zones 6-9.

Flower Fragrance: Asiatic lily flowers have little or no fragrance, and oriental lily flowers are large, exotic (often frilly), and heavily scented.

Cold Hardiness: Asiatics prefer colder winters to reset bloom (zones 1 to 9); Orientals (zones 6 to 9), down to zone 4 (if roots are mulched). Asiatic roots are not heat tolerant. Plants grow shorter and rarely require staking.

Staking: Asiatic lilies grow 1 to 6 feet tall. Oriental lily plants can grow 2-8 feet tall. Although stems are sturdy, Oriental lilies frequently need staking because their heavy trumpet flowers may topple over in windy or rainy weather.

Foliage: Asiatics generally have shiny 4 to 5 inch long leaves clustered close to one another on the stem. The leaf color is typically bright green. Oriental leaves are wider in the middle and longer, spaced further apart on the stem. Leaf color is typically dull green.

Dividing Bulbs: Asiatic lilies tend to double themselves from one year to the next. Oriental lily bulbs also increase in size and increase in bloom count each year. Bulbs should be harvested and divided every 3 to 5 years to prevent over-crowding in the bed.

Varietal Choices: Asiatics offer the widest choices of flower colors and choices from pastels to almost any colors of the rainbow. Asiatics usually come in single colors, while Orientals blooms are white, yellow and pink, with a different color on flower edges.

Bloom Season: Asiatics tend to bloom earlier in late spring. Generally, Orientals start blooming as Asiatic cultivars are finishing up. Mix the two, including hybrids, for a longer show in your garden.

Spice Up Dark Garden Spots With Heucherellas

Posted by Hugh on July 10th, 2016

‘Alabama Sunrise’ Heucherella (photo from Walters Gardens)

‘Buttered Rum’ Heucherella (Photo from Walters Garden)

Here come the heucherellas (x Heucherella), also called “foamy bells”. Heucherellas are hybrids that result from crossing two U.S. native genera: foamflower (Tiarella spp.) and coral bell (Heuchera spp.). Terra Nova Nurseries, a wholesale grower in Oregon, were the first to develop these hybrids. They possess the awesome foliage from both species parents.

One of my all-time favorites is ‘Sweet Tea’ foamy bells (Heucherella x ‘Sweet Tea’). It is a true garden performer. Large 4-inch wide palmate leaves become an orange colored tapestry which looks better from one month to the next. New spring foliage is bright orange. Some gardeners may opt to clip off flower stems to emphasize the rustic orange foliage colors. Leaves darken in the summer, and become a blend of orange and coppery shades in the autumn. Winter foliage is semi-evergreen in zones 6 and 7 and is fully evergreen further south.

Tiny creamy white, bell-shaped flowers open in late spring to early summer on sturdy stems, stand tall above the colorful foliage, and attract bees and butterflies.

Foamy bells want very little maintenance. They’re best planted in organically rich, well-drained soil and in a partially shaded area. Full morning sunlight and irrigation (or 1 inch rainfall weekly) are ideal condition. A new planting benefits from irrigation the first year; mulch plants to conserve soil moisture. Sweet Tea tolerates summer’s heat and dry periods because of its H. villosa bloodline (USDA hardiness zones 4–9).

Foamy bells are semi-evergreen through winter. Plants should be divided every 3-4 years in early spring before spring growth resurgence; remove and discard the old woody parts of the crown.

Leading cultivars at this time:

‘Sweet Tea’ – rustic orange leaves on 20 inch tall and 28 inch wide plants; tiny white flowers in early summer.

‘Buttered Rum’ – deeply cut, maple-shaped leaves begin caramel, changing to a rose-red for the fall. Sprays of small white flowers appear in late spring

‘Stoplight’- bright yellow leaves have a large, dark red blotch in the center which feathers out through the veins. Tiny white flowers on 12 inch tall stalks in late spring into early summer.

‘Sunrise Falls’ – brilliant chartreuse leaves with red veins; plants 8-12 inches tall

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.