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

Toadlilies In The Autumn Garden

Posted by Hugh on September 25th, 2018

Toadlilies -fall flowering

Tricyrtis ‘Sinonome’

Toadlilies (Tricyrtis spp.) are late season flowering perennials in the shade garden. Most perennials have finished blooming as their flower buds are forming. They’re native to moist woodsy environs of India, China and Japan and are Botanical members of the lily (Lilaceae) family (USDA hardiness zones 4-9). When properly sited, toadlilies are long-lived and require little care.

The plant name – “toad lily” – refers to the speckled flower colors. Flowers are borne in the axils of the leaves. Depending on species, plants grow 1 ½ to 3 feet high. Funnel shaped orchid-like flowers come in an array of spotted colors and are either star or bell shaped.

Toadlilies prefer part to full shade, and moist compost-rich garden soil. Under ideal conditions plants need little or no fertilizing. Plants should be protected from the wind particularly in hotter areas of the U.S. Otherwise, feed plants lightly once or twice during the summer with water soluble fertilizers such as Miracle-Gro™, Jack’s™, or Nature’s Source™. Mulching keeps the soil moist and suppresses weeds. Divide roots of the toadlilies in early spring and space new plants 18-24 inches apart.

Toadlilies live mostly untroubled by disease or pests. Anthracnose leaf spotting may pop up in wet summers. If so, clean up all leaf debris and discard in late winter. Deer may or not eat toad lilies? Rabbits can also be troublesome. Varieties with hairy foliage tend to repel critters.

Two species of toad lilies, T. hirta and T. formosana are currently most popular, Two species of toad lilies, T. hirta and T. formosana are currently most popular; they produce abundant purple-and-white blooms on 36 – 40 inch stems. Many new hybrid forms are finding their way into garden centers. ‘Miyazaki’ hybrids are known for their superior flowering, vigorous growth, hardiness, and disease resistance. T. hirta ‘Miyazaki Gold’ has gold-edged green leaves and ‘Moonlight’ has entirely golden leaves. T. macropoda ‘Sinonome’ and ‘Tojen’ has dark green foliage and lavender and white flowers; ‘Lightning Strike’ displays green and gold leaves and speckled flowers on arching stems.

Osage Orange As A Landscape Tree

Posted by Hugh on September 20th, 2018

“Hedge Apples”

Sturdy wood of osage orange

Osage orange (Maclura pomifera) has been declawed and neutered (USDA Zones 5-9). A member of the mulberry family (Moraceae), this tough prairie tree species is native to east Texas, Oklahoma and Arkansas. It grows fast @ 2 ½ to 3 feet per year. It is also called Bois D’Arc (pronounced “bow-dark”).

Osage orange is a dioecious species. Female trees are generally not recommended for landscape use because the fruits pose a considerable litter problem. The “hedge apples” are large 4-6 inch wide yellowish green fruits. Each may weigh 2 to 3 pounds and fall from the tree in October to become a maintenance headache. Female trees need a male tree pollinator in order to produce fruit.

Fierce ½- inch long thorns, hidden within the dense branches, can do lots of harm, even puncture a vehicle tire. The bark on mature trees is deeply fissured, with an orange-brown inner wood peeking through. The wood is hard, does not split or rot, and makes great fence posts. A century ago, in lieu of fences, farmers in the South Central states planted thousands of miles of hedgerows of osage orange. The tree suckers freely and becomes a quagmire of vicious thorns.

Osage orange is easily grown in adequately drained soils in full sun to part shade. The tree grows almost anywhere, in poor infertile, acid or alkaline soils, and dry or wet fields. It also tolerates drought, heat, cold and wind. Disease and pest problems are practically non-existent. Its foliage is tolerant of urban air pollutants.

‘White Shield’ (photo courtesy of J F Schmidt Nursery)

‘Wichita’ and ‘White Shield’ are fruitless and thornless (male) selections. Both cultivars are attractive landscape trees with deep green shiny foliage that turns a beautiful fall pale to golden yellow in fall. ‘Wichita’ grows slightly taller than ‘White Shield’, and its branching tends to be slightly more upright. ‘White Shield’ forms a rounded canopy, averaging 35 feet in height and spread. Trees bloom in late spring with tiny (mostly inconspicuous) green flower clusters.

Either cultivar is a good choice for large residential or commercial properties, city parks, and golf courses. Plant the tree under power lines or utilize as a deciduous windbreak.

Fall Lawn Care Tips

Posted by Hugh on September 15th, 2018

Lawn – new seeding

Newly cut lawn at Biltmore Estates, Asheville, NC

The fall season is “spring-time” for home lawn care. This is a great opportunity to apply grass seed, fertilize, and eliminate weeds in cool season lawns. In Tennessee (USDA hardiness zones 6-7), cool season grasses (fescue, bluegrass and perennial rye) are fertilized in mid-September with a high nitrogen-based fertilizer, available at most garden centers. Warm season lawn grasses (Bermuda and zoysia grasses) are not fertilized in the fall as they’re entering winter dormancy.

At least every 3-5 years, have your soil tested. A soil sample is a valuable tool in maintaining a healthy lawn. Most state agricultural universities offer this service for a small fee. Call your local Extension office to obtain a soil sample. A soil analysis report will be mailed (or emailed) to your home within 2-3 weeks. This aids that you do not waste money by over-fertilizing.

Fall is an excellent time to over-seed bare or thin spots over your cool season lawn. Fall is better than spring to take on major reseeding jobs, to include establishing a new lawn. Cool moist autumn weather is an ideal time. Weed pressure is a lot less than in the spring months.

Lastly, many lawn weeds are easier to control in the fall. Don’t wait until spring. Chickweed, henbit, wild garlic (Allium), and deadnettle are cool season annuals that are easierto eliminate in the fall. Actively growing perennial weeds such as dandelions, clovers, plantains, thistles, and spurges can be selectively treated in established lawns with phenoxy-base products such as Trimec™ or Weed B-Gone™. Caution: do not apply these chemicals to newly seeded lawns. Always read the package directions before using.

Success In Growing Franklinia Tree

Posted by Hugh on September 10th, 2018

Flower of Franklinia

Franklinia alatamaha at NC Arboretum in Asheville, NC

Franklinia (Franklinia altamaha) is a uniquely different large shrub or small tree. Great plant for the “I can grow anything crowd”. Rated hardy in USDA hardiness zones 5-8, I’ve never seen a landscape quality specimen in zone 5 and find that the tree performs best in zones 6 to 7. Success with growing franklinia hinges on purchasing a quality nursery plant, proper siting, and annual care, particularly in the first 2-3 years. Franklinia is only available from e-commerce nurseries and is best planted in late winter and early spring.

The species was first discovered growing in 1765 growing along the banks of the Altamaha River in southeastern Georgia by botanists John and William Bartram. The tree has been extinct in the wild since 1803. All franklinia trees are descendants from seedling propagated by the Bartrams in their Philadelphia, PA garden. Franklinia belongs to the tea family (Theaceae) and is closely related to Camellia, Stewartia and Gordonia (loblolly bay). The tree was named to honor Benjamin Franklin.

The tree’s most striking feature is the showy 2 – 3 inch pure white flowers with clusters of golden yellow stamens in the centers. The camellia-like flowers appear in late summer until frost. The blooms are sweetly-fragrant upclose. Narrow, oblong-obovate, glossy dark green 3-5 inch long leaves turn multi-shades of orange, red and purple thru the autumn season. Branching is upright and spreading to create an open airy. Ridged grey bark with prominent vertical white striations adds some winter interest.

Franklinia grows best grown in organically rich, medium moist, well-drained soils in full sun (in North) to partial shade (in Southeast). Franklinia has a fibrous root system, preferring soil environs similar to azaleas and rhododendrons. To repeat, soil should be humus-rich, excellently drained, and moderately acidic (pH 5.0 – 6.2).

Fertilize in early spring with an acidic based soluble fertilizer such as Miracle Gro®, Miracid®, or Hollytone®. Franklinia also favors an annual feeding of Epsom salts (magnesium sulfate) @ 1 Tablespoon per gallon of water per tree.

Franklinia is valued as a specimen or a plant collector’s tree. This hard to grow tree deserves a prominent location in your landscape. Plant tree in late winter and early spring. Hard to transplant because of its sparsely fibrous root system.

Wilt and soil root rot (Phythoptera) are the serious problems. Franklinia has a reputation for being difficult to grow. Proper siting of the tree is absolutely essential to avoid tree loss.

Working With Poorly Drained Soils

Posted by Hugh on September 8th, 2018

Soil Amending

Inkberry holly

As a rule, yews (Taxus spp.), Japanese hollies (Ilex crenata), azaleas (Rhododendron spp.), blueberries (Vaccinium spp.), and roses (Rosa spp.) are common examples of landscape plants that fail in poorly drained soils.

Holly cultivars like ‘Hoogendorn’ and ‘Soft Touch’ fair better in clay soils that most other Japanese hollies in the Southern Appalachian region (USDA hardiness zones 6 and 7). A better alternative is to substitute inkberry holly (Ilex glabra) in any planting bed where soil quality is suspect. A number of perennial plants die or are setback after spending their winter in waterlogged soils.

You can improve soil drainage by adding generous amounts of organic matter and coarse gravel such as sand, pea gravel, and perlite. It is difficult to estimate the exact amount to incorporate

Constructing and planting in raised bed is another option.

Not New –Still Top Landscape Performers

Posted by Hugh on September 6th, 2018

Abelia ‘Rose Creek’ in mid-fall at Biltmore Estates in Asheville, NC

‘Arctic Fire’ dogwood at Univ. of TN Gardens Knoxville

A senior gardener knows that many new plant cultivars (varieties) are often no better than what had come before. Many “superstar” shrubs, some released a decade or more ago, are still topnotch performers in many parts of the U.S. Here are six which I continue to recommend highly.

‘Low &Behold® Blue Chip Jr.’ Butterfly Bush is a super compact 18-30 inch tall shrub (or perennial) with deep indigo blue flowers above silvery blue foliage. For peak performance, plant in a full sun and in moist well-drained soil. Blue Chip Jr. is the smaller version of ‘Blue Chip’, another outstanding performer. (USDA hardiness zones 5-9).

Arctic Fire® Red Twig Dogwood (Cornus sanguinea) receives lots of notice for its brilliant red stems through the winter season. Bright green spring foliage turns gold-yellow in the fall. This compact 4-5 foot tall shrub grows well in either full to partial sun. (USDA hardiness zones 2-7).

‘Purple Pillar’ althea

Purple Pillar® Rose of Sharon (Hibiscus syriacus) flaunts a narrow columnar habit that’s a perfect fit in a small urban garden or large container. In mid-summer it produces showy 4- inch wide, semi-double, purple blooms. A mature shrub may be grow 16 feet tall and only 3 feet wide. Utilize as an accent specimen, narrow screen or hedge. (USDA hardiness zones 5-9)

‘Rose Creek’ Flowering Abelia (Abelia x grandiflora) is a compact version of a large old-fashioned shrub. Cultivar grows only 2-3 feet tall and 3-4 feet wide. New leaves emerge with a pinkish tone and matures bright green. White slightly fragrant flowers are produced from late spring to fall. In fall the flowers take on a copper-rose hue. (USDA hardiness zones 6-9).

Bobo® Panicle Hydrangea (Hydrangea paniculata) is a much smaller version of Limelight ® hydrangea. Compact growing Bobo grows 4 – 5 feet high and 3-4 feet wide. The white flowers are held upright on sturdy stems; Bobo has a long bloom period from late July into fall. (USDA hardiness zones 3-8).

Spirea thunbergii ‘Ogon’

Goldthread® Spirea (Spiraea thunbergii ‘Ogon’) is a compact growing (3-5 feet tall and wide) deciduous shrub with wiry arching branching. Clusters of tiny white flowers (each to 1/3” diameter) appear in early spring before its awesome foliage emerges. Goldthread spirea is a showy accent plant with narrow willow-like chartreuse colored leaves (to 1.5” long and to 1/4” wide). In most years, fall leaf color is average. (USDA hardiness zones 4-8)

‘Henry Eilers’ Coneflower (Rudbeckia)

Posted by Hugh on September 1st, 2018

R. subtomentosum ‘Henry Eilers’

quilled flowers

Called “sweet coneflower” (Rudbeckia subtomentosum), this U.S. Midwest prairie species is a long-lived perennial that grows in a variety of soils (USDA hardiness zones 4-8). Sweet coneflower prefers full or partial sun (6 hours minimum) and a moist well-drained loamy soils. It is highly drought tolerant after its first year in the garden.

Established plants emerge in mid-spring as a rosette of leaves and grow rapidly to 4-5 feet in height. Basal foliage is toothed, gray-green leaves (lower leaves are 3-lobed). The green stems and leaf undersides have a downy texture, a covering of many fine hairs.

Flowers of ‘Henry Eilers’ are uniquely different — the yellow petals (rays) are rolled instead of flat, giving the flower a quilled appearance. The ray petals surround the purplish-brown dome center. The 3-inches wide flowers bloom in clusters atop sturdy upright branched stems from very late July thru September.

The unique flowers attract numerous bees, butterflies, and seed feeding birds such as cardinals, finches, and jays. Snip flower stems to add to indoor decoration. Deadhead spent flowers to encourage additional bloom. Dark gray-green 3-6 inch long leaves, some 3-lobed, are found around the plant base along with smaller unlobed ones. Leaves emit a mild sweet vanilla or anise smell when crushed.

Fertilize at planting time and annually in the spring with a slow release product such as Osmocote™ or Nutricote™. No serious insect or disease problems trouble this coneflower species. Do not crowd plants as powdery mildew may occur. Taller plants may need some support, particularly if grown in partial shade.

Plants should be propagated by crown divisions in early spring. If grown from seed, only 20% may display the quilled flower trait.

Editor’s note: some species of Rudbeckia spp. are also called “Coneflowers”. In general, coneflowers are in the genus Echinacea spp.

Growing Morning Glories

Posted by Hugh on August 28th, 2018

Mornng glory vine

Field bindweed (invasive)

Morning glory vines (Ipomoea tricolor) add a dash of old fashion charm to today’s gardens. YES! these aggressive vines demand a high degree of attention. Their funnel or tubular-shaped flowers open in the morning and close late in the afternoon. In a single growing season, vines may grow 6 to 12 feet and more (depending on variety). Morning glories will also aggressively self-seed.

Vines bloom non-stop from June to October. Flower colors are available in purple, blue, red, white, pink and bi-colors. Many gardeners opt to grow morning glory vines to cover trellises, pergolas, arches and fences. Grow some in hanging baskets and train vines to drape over the sides.

Morning glories are usually grown from seed and may be started indoors 4 – 6 weeks before the last spring frost. Where the growing season is long, direct seed into the garden or a large container after all threat of frost has passed. Select a site that gets plenty of sun. Morning glories prefer moderately fertile, well-drained soil that needs to be kept consistently moist until the vine(s) are well established. Morning glories bloom their best in full sun.

Soak the seeds for 24 hours prior to sowing to spur higher numbers and faster germination. Distribute the seeds and cover lightly with soil and water thoroughly. Irrigate every few days if rainfall is light. Some gardeners will pre-start the seeds in peat pots and transplant them after 4-6 weeks.

Fertilizing is usually not necessary. Feeding liquid fertilizer, such as Miracle-Gro or Jack’s monthly, will spur increased growth and flowering. Be careful… do not overfertilize as this can produce more foliage than flowers. To prevent unwanted self-seeding, old flowers should be completely removed before they form seed pods, an almost impossible task.

Morning glory vines are generally not troubled by diseases or pests. When not properly sited, they may be infected with fungal leaf spot, rust, and wilt diseases. Aphids, leaf miner, spider mites and caterpillars may also pop up. Deer will browse on the leaves and vines. The seeds are poisonous.

Morning glories are often mistaken for their weedy white blooming cousin, field bindweed (Convolvulus arvensis), also called Creeping Jenny. Field bindweed, a hardy perennial vine, spreads by deep roots and is nearly impossible to get rid of. Its deep winter hardy roots allow bindweed to overwinter in colder climates to return again and again. Field bindweed blooms either white or pink flowers; the flowers and leaves are smaller than morning glory.

Texas Elephant Ears Study*

Posted by Hugh on August 23rd, 2018

‘Gecko’ (left) ‘Madiera’ (right)

Dr. Jared Barnes and colleagues at Stephen F. Austin University in Nacogdoches, Texas, trialed 46 Colocasia species/cultivars over two years to determine what performed best over a two-year growing period. First of all, Nacogdoches is in east Texas (Zone 8-b) and typifies the upper coastal plain, stretching from there east to South Carolina. Cultivars were grown in full sun and ratings were taken every two weeks during the growing season on a 1 (poor) to 5 (perfect) scale.

Only two cultivars earned a ranking above 3.5 in both of the trial years: Colocasia esculenta Madiera is commonly referred to as elephant ears, however, it has two traits that set it apart from the green giants you may be thinking of. First of all, Madiera about a third to half the size of the green forms of C. esculenta. Secondly, the foliage is a deep purple, making it a very striking garden plant. Listed as Zone 7 hardy, gardeners farther north can grow it, harvest tubers in the fall, store the tubers in a cool, dry location in a paper bag, and replant the following year.

The second outstanding performer is C. esculenta Red-Eyed Gecko (a Plants Nouveau introduction). It grows about 4-feet tall and wide boasts chartreuse foliage with a red spot in the upper side of foliage where the petiole is attached on the underside of the leaf. Variety listed as hardy to Zone 8.

*Information and photos reprinted with permission from Dr. Michael Chappell published 8/10/2018 edition of Ball Publishing, Nursery & Landscape Insider e-newsletter editor.

Ligularias For Moist Sites

Posted by Hugh on August 20th, 2018

Dark foliage of Ligularia ‘Marie Britt Crawford’

L. stenocephala ‘The Rocket’

Ligularias (ligs) are big leafy perennials whose roots must be kept constantly moist so that plants don’t wilt or “faint”. An established plant may tolerate several days in dry soil, yet the droopy foliage will recover from the water loss each night. Several species are tropical (under the genus Farfugium). Bigleaf ligs (L. dentata) and narrow-spiked ligularias (L. stenocephala), aka “golden ray”, grow well in temperate climes (USDA hardiness zones 6 and 7).

Leaves of some varieties may size up to 15-20 inches across. Ligs often suffer from bouts of fainting in the mid-afternoon due to summer heat and water loss from transpiration. Plant may wilt even if the soil is moist. By early evening the leaves mostly recover.

Lig’s showy bright yellow or orange flowers arise above the foliage in early summer. You may opt is cut-off the flower spikes in favor of lustrous 20-inches wide, coarsely tooth round foliage. Ligularia ‘Marie Britt Crawford’ is one such variety. Narrow-spiked ligs produce bright yellow or orange flower spikes, 2-5 inch flowers and 18-24 inch racemes and triangular, deeply toothed leaf margins.

Good site preparation and minimal annual maintenance will give ligularias a long life in a perennial garden. Set these perennials in moist, even soggy soil under partial sunlight, preferably morning sunlight. Ligs can be sited in boggy ground near a pond or a water garden; however, never submerge ligs in water. Provide lots of organic matter to the soil, a boggy location and this shade giant is luxurious.

Pest control is simply a matter of controlling slugs and snails from devouring the leaves, which create a “shot-hole” appearance in the foliage. Ligularias are propagated by division, generally in the spring or late in the summer. Clumps should be divided every 4-5 years.

Special Planting instructions: dig a hole large enough to accommodate a 3-5 gallon size container. Line the bottom of the hole with a plastic liner to retain moisture around the roots and to reduce the need of irrigation. Fill the hole with rich potting soil or a soil mix containing high amounts of humus or compost.

Leading Temperate Varieties:

L. stenocephala ‘The Rocket’ – tall 4-6 feet high narrow spikes of bright-yellow daisy flowers on purplish black stems and jagged-edged green leaves.

L. stenocephala ‘Baby Rocket’ – compact 2 1/2 – 3 foot selection above with large, serrated, dark green leaves and a bouquet of mustard-yellow floral spikelets on multiple chocolate stems.

L. dentata ‘Desdemona’ – rounded dark-green leaves with a purple backside; tall stems bear clusters of bright golden orange 3-3½ inches daisy flowers.

L. dentata ‘Orthello’ – large, rounded dark-green leaves with a purple underside; tall 3-4 feet tall floral stems bearing clusters of bright golden orange 3-3½ inches wide daisy flowers.

L. dentata ‘Britt-Marie Crawford’ – large, glossy, purple-black leaves and bold daisy-like orange-yellow flowers.