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

Bergenias (Pigsqueak) Gaining More Respect

Posted by Hugh on February 8th, 2015

Bergenia As Ground Cover Planting in Downtown Indianapolis

Heart-leaved bergenia (Bergenia cordifolia) is a clump-forming perennial indigenous to Russia (USDA hardiness zones 3-9). It has been coined the name “pig squeak” because of the noise produced by rubbing a leaf between your thumb and finger.

Bergenias are planted most effectively enmasse as a ground cover. They spread slowly by rhizomes and tends to seed-in readily. Over the years bergenia tends to naturalize in moist rich soil.

Its rosette growing habit is similar to a strawberry or an African violet plant. Round heart-shaped leaves are thick, glossy and dark green; leaves measure to 8 to 10 inches across. Plants are 12 to 15 inches high and wide in spread. Foliage often takes purplish-bronze tint over a cold winter. In the warm South foliage is evergreen but may become ratty and torn up in northerly zone 6 and colder.

Small showy pink or white flowers (depending on cultivar) emerge within or above the foliage on thick stalks up to 16 inches tall in April or May, depending where you garden.Promptly remove spent flowering stems if you do not want bergenias to multiply by seed.

Bergenia grows in average well-drained soil in part to full shade. It prefers moist, compost-rich ground. Fertilize bergenias in early spring as new growth starts. Mulching is highly beneficial as well as irrigation in dry shade. Prune off all damaged foliage by late winter before new growth and flowering begin.

This shade loving perennial excels as a ground cover in woodland gardens; utilize in dabbled sunny areas in flower beds, rock gardens, or as edging along pathways. The high gloss foliage is frequently utilized in floral arrangements. No serious insect or disease problems bother bergenias. Rabbits and deer stay away from bergenia.

Leading Cultivars:

‘Apple Blossom’ – large pale pink flowers on red stems that rise above glossy green leaves.

‘Bressingham White’ – flowers open pink but age to white; burgundy fall foliage.

‘Winterglut’ (‘Winter Glow’) – reddish-pink spring flowers; dark green summer leaves finish mottled red and orange in fall.

‘Flirt’ – a new compact hybrid form with dark green (almost black) glossy foliage; large deep pink blooms on short stems.

New Bergenia ‘Flirt’ from Terra Nova Nurseries

Support Tomato Plants

Posted by Hugh on February 6th, 2015

Trellised tomatoes

University research demonstrates that yields are lower for staked tomatoes. Staking tomatoes is not absolutely necessary, but harvesting tomatoes on the ground becomes more difficult. Dirt and disease blemishes on fruits laying on the ground necessitate grading, cleaning, and disposing of culls.

Most tall growing indeterminate varieties are best supported off the ground in some manner to prevent loss of fruit from rots and sunburn. Wooden stakes and caging are the most common methods of support.

Wire caging offers the highest yields. Wire cages should be a minimum of 18 inches in diameter and constructed from heavy-duty reinforcing wire that is difficult to bend. Cages wrapped with clear plastic to a height of 18 inches provide some protection from cold winds and blowing sand. Plants in cages are generally not suckered.

Traditionally, indeterminate tomato varieties are individually staked, suckers removed, and tied with cloth strips, soft cord, or twist ties weekly until they reach the top of the 6 feet tall stake. Trellising is an alternative method. Tomato plants are supported by nylon cords that runs (weaves) from stake to stake, down the row on both sides, all supported on heavy duty poles or metal stakes at several heights.

Tomato plants develop many branches (suckers) as they grow. A common practice to remove the suckers to encourage larger and earlier fruit yields. Sucker removal make tying and spraying a lot easier. Better sunlight penetration and air circulation around plants leads to less leaf spot problems.

‘Biokova’ Cranesbill Dependable Year-Round Ground Cover

Posted by Hugh on February 5th, 2015

Geranium ‘Biokova’

Biokova is not a new geranium, aka cranesbill (Geranium x cantebrigiense ‘Biokova’). Its exceptional landscape performance has earned the 2015 Perennial Plant of the Year designation. Cranesbills are highly dependable perennial ground cover for partial sun to partial shade landscape sites (USDA hardiness zones 5-8).

Among the better choices of cranesbills, ‘Biokova’ has proven exceptionally reliable here in the Southern Appalachian region (USDA hardiness zones 6 and 7). Flowers open white with a slight pinkish blush. Heaviest bloom occurs in May over 2-3 week period. Plants bloom intermittently through the summer into fall if kept actively growing.

Individual plants grow in a circular pattern, 1 foot high and 3 feet in spread, eventually to merge into dense ground cover. Biokova can also be included in a rock garden or containers. In cold areas, blemish-free dark green summer foliage turns burgundy red in late autumn. In its southern range Biokova foliage is evergreen. At the start of spring cranesbills look its best if closely mowed back.

Cranesbills grow best in a compost-rich well-drained soil. Few disease and insect problems plague cranesbills when they’re properly sited. They should be irrigated until established, usually within one year. Biokova displays moderate drought tolerance but is best irrigated during prolonged seasonal dry spells to keep foliage looking fresh.

Biokova is a constant feeder and benefits from two applications of granular 10-10-10 fertilizer in early spring and a second in mid- to late June @ 2 lbs. per 100 square feet of landscape bed.

Positive Facts About Tree Of Heaven

Posted by Hugh on February 2nd, 2015

Tree of Heaven in Late Summer in East Tennessee

Tree of heaven (Ailanthus altissima) is a hated tree and tagged noxious and invasive across the U.S. (USDA hardiness zones 4 to 8). This aggressive species is indigenous to China and seems almost without limits as to where it takes root across the U.S. It has numerous nicknames, including “trash can tree”. It is the tree featured in the 1943 book and 1945 movie “A Tree Grows In Brooklyn” (tree has little to do with the story).

The tree grows in a wide range of soils including poor ones, on sites where few other trees would prosper. It prefers full sun, but can cope with shady environs. Roots sucker freely and can form large colonies or thickets. It grows almost anywhere, even from the cracks in concrete sidewalks or asphalt parking lots. It also self-seeds freely. Across the U.S. tree of heaven grows along roads and fencerows.

Tree of heaven exhibits a lush tropical look; its pinnate compound leaves are 1 to 4 feet in length. Growth rate is an incredible 3-5 feet annually, eventually 40-60 feet tall and 30-40 feet spread and a loose, open canopy. Tree grows shorter in urban areas.

Its foliage is highly resistant to air and ground pollutants very common in large urban areas. Its leaves help to purify the air and cool the planet. Its shade (cooling) value worldwide has been estimated as 0.5 of 1º F. Serious insect or disease problems do not exist.

Plant scientists need to research this species. Its rapid growth rate might be harnessed for green biomass as a future biofuel resource. Perhaps, its invasive nature could be reined in. Little research work has been done to find or breed a sterile form.

Its root suckering is quite variable among the Ailanthus population. Some trees sucker very little.

Tree Of Heaven Grows Almost Everywhere (Unfortunately)

Posted by Hugh on January 30th, 2015

Tree of Heaven -late summer seed heads

Tree of heaven (Ailanthus altissima) is one of the most aggressive trees on planet Earth (USDA hardiness zones 4 to 8). This large tree, indigenous to China, was introduced in North America in 1748 and brought to New York City in 1820 as a street tree and a food source for silkworm caterpillars.

The tree tolerates a wide range of soils including poor ones, on sites where few other trees would survive. Growth rate is an incredible 3-5 feet in one season, eventually 40-60 feet high and 30-40 feet in spread with a loose, open canopy. The tree grows shorter in urban areas.

It prefers full sun, but can cope with partial shade. It is highly tolerant of deep shade and urban pollution. Roots sucker freely and can form large colonies or thickets that choke out native plants. It also self-seeds freely.

It grows almost anywhere, even from the cracks in concrete sidewalks or asphalt parking lots. Its roots damage pavement and building foundations. In most states, tree of heaven is commonly seen along roads and fencerows and is classified as a noxious weed in many states.

Its pinnately compound leaves are 1 to 4 feet in length which gives tree of heaven a lush tropical appearance. Basal leaflets display large gland-tipped teeth. Leaves and stems emit a foul stench when crunched.

Tree of heaven is primarily dioecious (separate male and female trees). Male flowers give off an unpleasant odor. It blooms June into July and flowers are greenish. Female trees produce reddish (maturing tan colored) single-winged samara fruits which are disseminated in early fall. A smooth medium gray bark covers the trunk(s) and main branches. Branch wood is weak and tall trees may self-destruct in strong winds.

Leaves are resistant to most urban air and ground pollutants. It has no serious insect or disease problems. Tree of heaven is difficult to eradicate. The tree drops loads of leaf and stem debris over lawn areas.

2015-16 Hosta Awards Announced

Posted by Hugh on January 28th, 2015

Chosen by American Hosta Growers*, the winners are…

2015 Hosta of the Year

Hosta ‘Victory’

Victory is an impressive plant. It forms giant vase-shaped clumps with large, shiny leaves with green centers and margins that change from greenish yellow in the spring to creamy white by early summer. Victory is big hosta that grows 30 inches high by 54 inches across and produces near white to light lavender flowers in the mid-summer. Touted for its smooth textured foliage with thick substance, Victory is a great addition to shady landscapes.

2016 Hosta of the Year

Hosta ‘Curly Fries’

2016 AHG Hosta of the Year will be Hosta Curly Fries. This is a novelty hosta with extremely rippled, narrow chartreuse leaves. The mature plants are peppered with red speckled petioles. Curly Fries is a smaller hosta, forming clumps that grow to 6 inches high and 16 inches across. Just morning sunlight will bring out the best foliage color.

* Information and photos provided by Perennial Pulse e-newsletter.

Winter Blooming Flowering Apricot

Posted by Hugh on January 28th, 2015

Prunus mume on ETSU campus in Johnson City, TN

Upright tree form

Flowering apricot (Prunus mume) is native to southeastern Asia(USDA hardiness zones 6-8). It is primarily grown for its mid to late winter bloom of pink flowers.

This small 15-20 feet tall tree grows in average well-drained, acidic soils in full sun to partial shade. Avoid planting in heavy or wet soils. Most abundant flowering occurs in full sun. In the deep South leaves may scorch in full day sun. Prune, if needed, immediately after flowering.

A young tree tends to be branched upright. Spicily scented pink flowers bloom anytime – during a warm winter respite or in early spring. Flowers display red calyxes and yellow stamens. Flowers are followed by small 1-inch diameter, fuzzy-skinned, green to yellow apricot fruits. The ripe clingstone fruits are harvested in mid-summer and made into jams and preserves.

Occasionally, cold winter and spring temps damage flowers and subsequent fruits. Bloom buds have a staggered dormancy so that only the open flowers and swollen buds are damaged. This ensures a long period of flowering. If left unpicked, fruits may cause a mess on lawns and sidewalks. Birds help in the cleanup. Potential insect pests include aphids, scale and borers. Bacterial canker and brown rot on fruits are probable disease problems.

Flower buds are set in fall; fall-winter pruning removes some flower buds. Flowering apricot should be prune within 4-6 weeks after flowering. Annual pruning encourages new vigorous shoots that eventually bear the future flower buds. Flowering apricots are short-lived, around 15-20 years in the U.S.

Numerous cultivars are available from on-line nurseries. ‘Peggy Clarke’ struts rose-pink double flowers; ‘Rosemary Clarke’, early white petalled double-flowered form; ‘W.B. Clarke’ has double pink flowers, and graceful weeping form.

Hiring A Tree Service

Posted by Hugh on January 24th, 2015

Arborist Pruning Pine at Chicago Botanical Gardens

The trees around your home do much more than provide seasonal beauty and cooling shade in the summer months. Just as you need to get an occasional haircut, trees (and shrubs) need pruning as well. Homeowners should invite a trained arborist to inspect their trees every 5 -7 years.

First, select a tree pruner who is licensed and bonded. Be certain that he or she shows their business credentials. Second, how many years has the company been in operation. Longevity is a good thing. Third, when will the work start and finish. Get a firm date. Don’t pay fully until the agreed upon job has been completed. A small down payment for a multi-thousand $$ job, perhaps 20% down, is okay.

Most companies are listed in telephone book (who reads that anymore) or on-line or on Angie’s List. Personal reviews from former clients who are pleased with a completed job is pretty good endorsement. Drive around and observe the aftermath of their handiwork.

Finally, consumers are in the driving seat when planning tree maintenance. Immediately following a severe storm (hurricane, tornado, ice storm) is never a good time to negotiate price. Oft-season pruning times (winter) are better times to request a cheaper rate.

Procure at least three bids and select the best one for you. Many times it is not the lowest bid that wins the job.

Sycamore Maple Performs In Cooler Regions

Posted by Hugh on January 21st, 2015

Last Leaves of Summer

Bark on Mature Sycamore Maple

Sycamore maple, aka planetree maple (Acer pseudoplatanus) is indigenous to northern and central Europe where it is a popular landscape tree. Very commonly planted in the northeastern U.S. in the early 20th century, this large 50-60 foot tree is rarely found today (USDA zones 4 and 7). A mature specimen in Jonesborough, Tennessee (zone 6) is over 80 feet in height.

The popularity of native red (A. rubrum) and sugar (A. saccharum) maples is the likely reason that it is no longer planted. Sycamore maple exhibits subpar summer heat tolerance which excludes its use in the southeastern U.S. The 4 – 6 inch broadly palmate leaves feel sand-papery to the touch. Leaf petioles are 4-5 inches long. Mature specimen trees display grayish brown bark which chips off in tiny narrow strips to expose orange-red inner wood. Its green clusters flowers in spring contribute little to the tree’s overall stature; leaves turn a bland yellowish brown before abscising.

There are two diminutive cultivars which are more deserving your planting attention. ‘Brilliantissima’ exhibits salmon pink spring foliage which turns bright lime-green in summer. ‘Esk Sunset’ foliage starts off with pink, green and white variegation, and turns lemony green in the summer. Both cultivars grow very slowly, perhaps to less than a third the size of species (20-40 feet in height and 12-15 feet in spread).

Sycamore maple grows in average well-drained soil and is not pH sensitive, even high lime soils. Leaves are exceptionally tolerant of salt and urban air pollutants. Annual growth rate is fast and the upright branches of this hardwood maple are very sturdy. Sycamore maple distribute thousands of fertile double winged samaras (“whirligigs”)annually and seeds invade surrounding landscapes. Pennsylvania lists sycamore maple as invasive.

Sycamore maple is available from a number of on-line nurseries.

Take A Second Look At Canadian Hemlock

Posted by Hugh on January 18th, 2015

Large hemlock hedge at Biltmore Estate, Asheville, NC

Hemlock at Yewdell in Louisville, KY

Canadian hemlock (Tsuga canadensis) is a native evergreen species which is available in many forms: prostrate, globose, weeping, fastigiate and variegated (USDA Hardiness Zones 3-7). Its tremendous versatility as a hedging tree or shrub in planting sites is also a great reason to continue to include hemlock in the landscape. Hemlock may be planted in full sun to moderate shade and does quite well.

Negative publicity continues hurt the sales of this evergreen. For nearly a half century, hemlock wooly adelgid, a serious insect pest from eastern Asia, has devastated hemlocks in the eastern U.S. forest lands. Adelgid infestations continue to move across the country.

Plant scientists have developed workable strategies for nursery producers and homeowners to combat wooly adelgids. In addition, the severe winter weather of 2013-14 reduced adelgid populations in large landscapes and forest lands. Parasitic beetle releases in state forests are helping to reduce adelgid numbers. Pesticides continue to be very effective in managing this pest without environmentally damaging the treated areas.

The American Conifer lists over 250 cultivars of just Canadian hemlock. Many are slow-growing and somewhat pendulous.

Short List of Cultivars to Plant…

‘Cole’s Prostrate’ or ‘Cole’ – slow-growing, ground hugger ideal for rock gardens; or graft on a short standard; 3 feet after 10 years.

‘Everitt Golden’ – new spring growth with golden tints; compact 5 feet high by 4 feet wide shrub after 10 years.

‘Frosty’ – white tipped new spring growth that fades; 3-6 feet globe form after 10 years.

‘Gentsch White’ – slow-growing, globe form with variegated branch tips; 5-6 feet after 10 years.

‘Jeddeloh’- mounding or nest-like habit; 3-6 feet height after 10 years.

‘Lewis’ – dwarf with upright branched; 3-6 feet height after 10 years.

‘Sargentii’ – aka ‘Pendula’, broad spreading weeping form that can reach more than 10 feet high and 20 feet wide.

‘Watnong Star’ – new shoots almost white; needle arrangement appears star-like on strong 2-inch to 2½-inch shoots.

Worldwide, there are five other major species of hemlock other than Canadian hemlock. They are Carolina hemlock (T. caroliniana), western hemlock (T. heterophylla), mountain hemlock(T. mertensiana), and Southern Japanese hemlock (T. sieboldii), and Northern Japanese hemlock (T. diversifolia).