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

Sunset Cutie® Gaillardia

Posted by Hugh on June 5th, 2015

‘Sunset Cutie’ Gaillardia (photo by Paul Pilon)

New from PlantHaven is a new 15-inch gaillardia (Gaillardia x grandiflora) called Sunset Cutie® with red-bronze flowers edged in creamy yellow. It will leave a bright fiesta feel to our home landscape.

Sunset Cutie has a compact mounding plant habit. It will bloom nonstop on your patio this summer or in your perennial flower bed. It is hardy to Zone 5 to 9.

Grow gaillardias in full sun and well-drained soil or container media. Soil (media) drainage is an absolute key to plant and flowering longevity. Keep plant(s) adequately watered and fertilized. Feed container grown plants monthly with a water soluble fertilizer such as Miracle-Gro™, Schultz™, or Nature’s Source™.

Gaillarida or “blanket flower” is seldom bothered by deer. Deadheading keeps plant(s) blooming from late spring to autumn’s first frost.

Winter Damage On Crape Myrtles

Posted by Hugh on June 2nd, 2015

Crape myrtles suckering from base

Winter damaged crape myrtle

Extremely cold winters of 2013-14 and 2014-15 have damaged many cultivars of crape myrtles (Lagerstroemia x indica). Don’t assume that new crape myrtles are hardy; many are rated hardy only to zone 7. Several of the U.S. National Arboretum cultivars are hardy in zone 6. Gardeners living in the Mid-Atlantic or the lower Midwest states, where crape myrtles are iffy, frequently start over by cutting them back near the ground in spring and fertilizing.

Is your crape myrtle dead? First, determine if the tree (shrub) is alive? Nick the bark with your fingernail or a knife to determine if the wood is still green (living). Use a chain saw, pruning saw or loppers to cut the trunk(s) close to the ground. Within a few weeks green shoots will begin sprouting around the base. Choose 3 – 5 well-spaced shoots to become the new main trunk(s) and cut off the rest. Large specimens can sucker back and even bloom in late summer and the early days of autumn.

Fertilize every 6 – 8 weeks with a high-nitrogen fertilizer until mid-August and no more through the end of the year. Maintain 2 – 3 inches of mulch and keep soil and mulch away from the shrub/tree base. Irrigate crape myrtles bi-monthly in the absence of rainfall.

When replanting, set crape myrtles in the ground shallow and never deep in the planting hole. Stop the practice of hat-racking, commonly called “crape murder”, as it places a tree under stress and more susceptible to winter freeze damage. Do not prune crape myrtles in the winter months (early March in most areas).

Finally, select exceptionally cold-hardy cultivars, such as ‘Natchez’ (tree form, white blooms), ‘Hopi’ (shrub, medium pink), ‘Acoma’ (shrub, white).

Red Abyssinian Banana For Tropical Looking Landscapes

Posted by Hugh on May 24th, 2015

Red Abyssinian Banana in container

Ensete banana

Red Abyssinian banana (Ensete maurelii ‘Red Abyssinian’) is a tropical banana from high in the mountains of Ethiopia in eastern Africa. Its enormous reddish to purplish foliage and red – burgundy trunk adds a tropical presence to any garden. Compared to hardier banana genus Musa, Ensete does not produce root suckers (pups) nor is it a clump grower. All foliage originates from one trunk. By late September plant may grow 8 – 10 feet tall and 6 – 7 feet wide in temperate gardens and double that size in tropical regions.

Individual leaves expand to 10 feet or more in length. The green leaves orient upright and are splashed with vivid burgundy splotches over the new stems and foliage. Foliage color is more vivid if grown in full sun. Red Abyssinian can be planted in large containers or troughs and set on your deck or patio.

Red Abyssinian holds its foliage very upright on a burgundy colored pseudo-trunk. Spring/summer growth is extremely vigorous. This tropical banana excels in hot, humid, wet summers and rich fertile soils and fails when soil moisture and nitrogen fertilizer are lacking.

At the garden center your initial purchase may be a 18-inch starter plant from tissue culture, and in only 4 – 5 months it develops into a 6 – 8 foot giant. Beautiful flowers form only in tropical climates with a much longer hot weather to permit uninterrupted growth.

Select a large container greater than 24 inches in diameter at the base and weighted down to support what will be an enormous plant by late summer. Maintain your banana on the luxury diet with sun, water and liquid fertilizer.

Choose flowering bedding plants, large leaf hostas, vining ground covers, and/or ferns to complement Ensete banana in a container. In zone 8 and further south combine tropical gingers, spiky-leaved phormiums, and various palms.

Good News About Garden Impatiens

Posted by Hugh on May 1st, 2015

Impatiens Bounce Pink Flame at Univ. of Georgia Trial Gardens (photo by Meg Green)

Gardeners no longer have to give up growing garden impatiens (Impatiens walleriana). No, the worldwide disease outbreak of downy mildew on garden impatiens is not over. But new disease resistant cultivars of impatiens are arriving at garden centers this spring.

Two of the newest are: SunPatiens® Spreading Shell Pink and Bounce® Pink Flame (‘Balboufink’). Sunpatiens thrives in half-day to full sun. Bounce impatiens are New Guinea types and grow either in modest shade to half-day morning sunlight (zones 6-8).

Spreading Shell Pink, the newest addition in the series, is covered with lovely soft pink flowers from late spring to first fall frost. After transplanting a strong rootsystem takes hold quickly and these impatiens thrive in summer’s heat, rain and humidity. Plants have a vigorous spreading habit and plants maintain excellent plant form through the summer in full sun to light shade.

Bounce impatiens are interspecific hybrids with New Guinea impatiens (I. x hawkeri); they look like old-fashioned garden impatiens in plant habit, flower form and count, but are completely downy mildew resistant. One of four new cultivars in the Bounce series for 2015, Pink Flame boasts massive numbers of stunning, bright pink bicolor blooms on plants that are 12 to 18 inches high and spread.

Bounce and Sunpatiens are low-maintenance flowering annuals to grace your garden this year and many more. Both new impatiens are highly disease and pest resistant. Feed plants monthly with a water soluble fertilizer such as Miracle-Gro™, Daniels™ or Schultz™. Mulch at transplanting time and irrigate during moderate dry spells through the season.

All-America Selections (AAS) has picked out these two impatiens for their exceptional performance in the AAS container trials.

New Redbuds With Striking Foliage Abound

Posted by Hugh on March 21st, 2015

New Ruby Falls’ redbud

New ‘Rising Sun’ redbud

Over the past decade Eastern redbud (Cercis canadensis) has undergone a real facelift. This native spring flowering tree can no longer be solely identified by its green heart-shaped leaves. New foliage color choices will decidedly catch your eye and win you over. With some reservations most redbud cultivars fall within USDA hardiness zones 5-9.

Purple-leaf ‘Forest Pansy’ redbud, released over 70 years ago, continues to be very popular. Today, two gold-colored foliage cultivars, ‘Rising Sun’ and ‘Hearts of Gold’, are catching on with landscapers. The dark yellow tint holds all spring and summer long. Brand new Solar Eclipse™ flaunts striking peach-orange foliage.

In the white variegated leaf category is new Alley Cat™, selected by Allen Bush of Jelitto Seed. The variegated foliage does not burn or fade like old-timey cultivar ‘Silver Cloud’. Floating Clouds™, a new Don Shadow introduction, boasts green foliage generously splashed in white; it does not scorch in the summer sun.

Gardeners with limited space may opt for low weeping redbud forms. Old-timers like ‘Covey’ (Lavender Twist®) and ‘Traveller’ continue to be popular green leaf weepers. New weepers include Ruby Falls™ and Whitewater™. Ruby Falls is essentially a weeping ‘Forest Pansy’ with striking white and green variegated spring foliage. Whitewater is a tree weeper with green leaves sprinkled with white flecks.

Getting Your Greenhouse Ready For Spring

Posted by Hugh on February 18th, 2015

Clean Greenhouse Environment No! to hose nozzle on floor

Essential Clean Greenhouse Environment

Before starting new spring vegetable and flower plants, first take some time to make sure that the greenhouse is clean. Follow these three basic rules:

#1 – Repair or replace rotten or decayed wooden structural beams or posts, including benches. Be certain that water does not puddle on floors causing disease and insect breeding areas, mold, mildew and algae problems.

#2 – eliminate of over-wintering greenhouse pests, even if the area was unheated during the winter. Weeds and plant debris harbor overwintering insects, diseases, and viruses. Here is a short to do list:

Remove all weeds and plant debris. Aphids, spider mites, thrips and whiteflies may move onto newly planted crops from weeds.
Clean work areas and production surfaces first by sweeping and/or hosing down.
Clean up old growing medium left on benches and floors to reduce breeding areas for pests like fungus gnats, shoreflies and Western flower thrips.
Disinfect to kill all pathogenic organisms utilizing a number of commercial disinfectants, including hydrogen dioxide and quaternary ammonium compounds. Scrub up or dispose of previously used plastic pots and trays, tools and equipment.
Keep hose nozzles off floor.

#3 – Inspect all new incoming plants, even newly purchased plants and cuttings. Outside overwintering plants may have insects and scales and mites on them.

Most pre-emergent herbicides are NOT labeled for use in greenhouses; they may cause significant plant injury. Roundup® herbicide is labeled for application to greenhouse floors. Landscape fabric for weed prevention and new gravel on floors and under benches reduces weed populations. Follow the herbicide label for proper application rates and restrictions to prevent spray drift and volatility that could injure plants.

When potting up: inspect and discard plants with brown unhealthy roots; swellings on the roots (root knot nematode); abnormal leaf vein discoloration (foliar nematodes); mosaic ring spots, dark lines and rings (viruses); and chlorotic leaves (nutritional disorders).

In summary start out clean and make all efforts to stay clean.

Versatile Corona Lopper/Hand Pruners

Posted by Hugh on February 16th, 2015

Hand pruning mode for light cuts

Lopper mode for larger pruning cuts

When stepping out in my garden, a pair of hand pruners (shears) is the first tool in my pocket or belt pouch. A good pair of pruning shears is indispensable for snipping off old spent flowers and growth from perennials such as hostas, daylilies, peonies, et al; shrubs like rhododendrons, lilacs, hydrangeas; to clear away encroaching vegetation from a path; remove dead, pest ridden, and diseased twigs or small (1-inch diameter) branches.

Over the years I’ve owned a number of pruning shears from top manufacturers. The Corona #60 hand pruner has been my “go-to” pruners, backed up by the Corona 19 inch long lopping pruners.

As stated in a previous blog, my prerequisites for a good pruning shears are:

Blades forged from high grade forged steel, less likely to rust and stays sharp longer
Comfortable hand grips, less prone to cause calluses after heavy use
Colorful hand grips so pruner is not easily lost in the garden
Trustworthy locking mechanism that, when engaged, the blades close and don’t reopen in your pocket or belt pouch. Cutting action does not lock up by a faulty locking clip
Stays sharp longer and cuts almost effortlessly
Scissor cut and not anvil type

The Corona BP7450 is a convertible pruner + lopper. The lopper is designed for making cuts up to 1 1/4 inch in diameter. This lightweight pruning shears cuts through soft green stems and small twiggy wood effortlessly. Or convert it into a lopping shears for cutting through thicker branches up to 1 1/4 inch diameter.

This convertible pruner + lopper is mostly available on-line. Eventually, blades wear out or become rusted (if left outdoors–always a no-no for most garden tools). Most parts are available from Corona dealers and some orchard supply companies across the U.S.

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.

What Roses Need

Posted by Hugh on January 13th, 2015

Double Pink Knockout at UT Gardens, Knoxville, TN

Rosa ‘Shockwave’

A goal of most rose gardeners (rosarians) is to grow them almost maintenance free. The improved shrub roses introduced almost two decades ago have brought this too reality. Rose series such as Knockout®, Home Run®, Drift®, OSO Easy®, Carefree® and Meidiland™ are among the best.

No matter the pedigree of the rose, selecting a poor site, doing something wrong, and new disease problems can disappoint your love affair with roses. Providing a good environment makes growing roses a lot more enjoyable:

Plant in soil with good moisture drainage
At least 6 hours of sunlight
Adequate spacing between shrubs to allow good air circulation
Shelter from high or drying winds
Little competition from other plants
Irrigate ground but keep foliage dry (drip, soaker hoses); best time to water is early morning
Fertilizers: either a water soluble fertilizer (3-4 times in growing season thru early September); or 10-10-10 (in early spring and mid-July); or slow release fertilizer once in early spring.
Organic fertilizers (as alternative):

N (nitrogen) -horse manure – yes!; cow manure –no! (full of weed seeds)
P (phosphorus) – roses crave P, very important; sources: bone meal, rock phosphate
K (potassium) – improve summer heat tolerance
Minors- Fe (chelated iron) and Mg (Epsom salts)

Mulch with 2-3 inch layer of pine needles, bark chips or nuggets around bushes, but not against trunks.
Keep roses weed-free as weeds compete and also attract harmful bugs and diseases
Prune roses in late winter or spring when dormant or starting to bud out
Prune in summer to remove disease wood, particularly rose rosette or other virus problems

Is Your Tree A Hazard?

Posted by Hugh on December 30th, 2014

Fall Leaf Color of Silver Maple With Good Form

Is a dangerous tree lurking in your yard, ready to tumble down on your house or car? A well shaped landscape tree with a full canopy (top) and undergoes a safety checkup every 3-5 years is rarely at risk. When the weather forecaster is predicting a hurricane or an ice storm, it’s generally too late to call a local certified arborist.

Category storms are out of the ordinary and even healthy trees are likely to receive some injury. You should not wait until a storm has caused damage. Tree maintenance goes along with tree ownership. A tree’s health, like people’s, changes over time. Middle aged trees are less hazardous than old mature trees. Age plus a category storm may inflict significant damage to render a tree hazardous.

Different tree species possess different mechanical strengths and decay mechanisms. Weak-wooded species considered hazardous include silver maple (Acer saccharinum), cottonwood and hybrid poplars (Populus spp.), willows (Salix spp.), boxelder (Acer negundo), and tree-of-heaven (Ailanthus altissima).

Location is a key factor. A tree not growing around people, homes, and autos is not likely to inflict serious damage if it falls. A tree growing in a public park should be inspected periodically, then pruned or removed. However, a residential tree with a large decay cavity likely should be removed at once.

Trees may show decay or cavities along the main trunk(s) and branches. Timely pruning usually cures most ills. It’s kind of like going to the dentist. A cavity represents wood decay and branch weakness. Decay can be slowed by cleaning out the wound and spraying a pesticide to prevent wood boring insects from habitating.

A certified arborist can measure the extent of the tree decay using a Resistograph®. A hollow tree cavity is not always hazardous. Tree cavities that are surrounded by at least one inch of solid wood per six inches of tree diameter are unlikely to fail according to good scientific support.

You should hire only a certified, licensed and insured arborist. Certification is awarded by the International Society of Arboriculture (ISA) following extensive study and testing.