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

Fritillarias – Very Different Spring Flowering Bulb

Posted by Hugh on September 15th, 2016

Red Fritillarias Interplanted with other bulbs

Yellow variety ‘Lutea’ at Keukenhof, Netherlands

Crown imperial (Fritillaria imperialis), aka fritillaria, is an impressive spring flowering bulb that is native of Southwestern Asia to the Himalayas (USDA hardiness zones 5-8). In late April to May, large drooping orange, red, or yellow bell-shaped flowers are topped by a small pineapple-like tufts of leaf-like bracts. The leafy fringe on top resembles a crown, hence the common name “Crown Imperial”. All parts of the plant emit a skunk-like odor.

Individual bulbs grow 3-5 feet tall and 1 to 1½ feet wide. Some gardeners will inter-plant multi-rows of mid- to late-season tulips, daffodils, et al. with the taller growing fritillarias. Each bulb produces flowers on top of a thick, stout, upright flowering stem. Lance-shaped green leaves (to 6 inches long) have wavy margins and appear in whorls around the lower one-half of stem.

Fritillarias are at their best in full sun. Plant bulbs 6-8 inches deep in compost-rich, moist, very well-drained, high pH soils. Space bulbs 12 or more inches apart in autumn for adequate winter chilling in the winter soil. Protect from high wind or be prepared to stake stems.

According to Brent Heath, from Brent and Becky’s Bulbs in Gloucester, VA, “if you garden in most areas of the Eastern or Midwestern U.S., fritillarias are very challenging to grow. Gardeners in the Southwestern U.S. have the best luck with growing fritillaries”. They suffer in heavy clay soils which tend to stay very wet during summer and winter months, resulting in bulbs to rot in the ground.

Foliage dies back by early summer as the bulbs go dormant. Bulbs are large but fragile and are best left undisturbed once planted. Bulbs are best mulched with medium to coarse bark mulch to provide winter protection. Fritillarias resent highly moist soils, particularly in the summer and winter months which leads to bulb rot. Plants are also susceptible to leaf spot, rust and mosaic virus. Most critters like voles, squirrels and deer leave fritillarias alone.

Tip: Excellent soil drainage is the key. Plant on a bed of gravel or coarse sand. Set each bulb on its side to keep water from collecting in the depression at the top of the bulb to prevent or reduce bulb rotting.

To create a spectacular display, plant 6-12 bulbs in the rear of a spring flower border where they can be clearly viewed but their unpleasant flower and foliage fragrance will not picked up.

House Plant Basic Care Tips

Posted by Hugh on September 12th, 2016

Collection of House Plants at Biltmore Estates, Asheville, NC

Two varieties of Bromeliads In Summer Shade

Tropical house plants decorate homes, restaurants, shopping malls, and work environments (USDA hardiness zones 8 through 11). Many will grow in medium to low light areas of your home, work, and where flowering plants do not perform. Here are some basic house plant tips:

They languish in areas where temperatures are below 55 °F. Dry room air often results in brown leaf edges. Room humidity can be raised by setting a plant on a tray of wet gravel (but not sitting in standing water), or close by a room humidifier. Simply grouping several plants close together will raise the humidity.

Spring, summer, and fall feed plants every 2 – 3 weeks with a water soluble “house plant fertilizer” at one-half package directions. Winter feeding is usually unnecessary or performed once monthly. Once monthly, flush the soil with water to leach out excess fertilizer salts.

Plants may be moved outdoors in summer and placed under a large shade tree in filtered or indirect light and temperatures between 55 – 90 °F.

Occasionally rinse large leafy foliage plants with a garden hose or bath shower to remove dust and pollen. Turn large foliage plants regularly to supply adequate light to all sides of plant(s) and prevent it from reaching outward toward light source.

Over time bottom leaves will brown and die out. This is natural. Snip them off to keep the plant tidy.

Water thoroughly and as needed. Never overwater your houseplants. Irrigate with non-fluoridated, room temperature water to avoid burning the foliage.

Repot annually. Choose a container 2 inches larger than the existing one. Shake old soil away from roots and replace with a well-drained potting mix.

Disease and insect problems are rare, but occasionally happen. Inspect plants every few weeks for scale, mealy bugs, mites and aphids. Their feeding symptoms cause leaf curl, speckling, or bronzing of the foliage. In particular, inspect underside of leaves for webbing. Spray with insecticidal soap or neem oil every one to two weeks until pest has been managed.

Caution: The leaves of some house plants are toxic and should not be ingested. While most are not poisonous and cause death, some may cause temporary swelling of the tongue and throat, leading to a temporary loss of speech or stomach aches. Some common examples are dumbcane (Dieffenbachia), Chinese Evergreen (Aglaonema). Sap from Crown of Thorns (Euphorbia) may result in skin irritation. Keep such plants away from children or pets that might be tempted to taste it.

Some Zone 7 Camellias Survive In Zone 6 As Well

Posted by Hugh on September 10th, 2016

Mid-November blooming ‘Shishigashira’ camellia in my zone 6 garden

Camellia sasangua ‘Kanjiro’

A short list of early blooming Sasanqua camellias possess the ability to do grow well in zone 6 areas. In my opinion, the zone 7 cultivar ‘Shishigashira’ steps to the head of the class. It is a November bloomer that has proven to be exceptionally cold hardy dwarf variety.

The good folks at Cam Too, a camellia wholesale nursery in Greensboro, NC, highly recommends these hardy cultivars: ‘Kanjiro’, ‘Hiryu’, ‘Yoi Machi’, ‘Crimson Candles’ and ‘Korean Fire’. All are (Camellia sasanqua) bloodline except Korean Fire (C. japonica) .

Their vegetative and floral hardiness is excellent–even following nights in the low 20’s, the open flowers still held their color. Plants exhibit upright branching and will be full in good light exposure. all would be cold hardy to zone 6-b and would flower for you.

Shishigashira – hot pink semi-double flowers; low and wide spreading habit.

Kanjiro – pink semi-double bloom edged in red with golden stamens and a slight fragrance; dense semi-weeping habit; glossy, dark green foliage.

Hiryu – deep crimson red, rose-form, double flowers in early fall; compact shrub, and more sun-loving than most camellias.

Yoi Machi – vigorous grower with white petalled flowers with pale pink margins; it blooms from late fall into spring.

Crimson Candles – vigorous grower and disease resistant; small bright rose-red single flowers in early fall; new foliage is bronze-red.

Korean Fire – single red flowers which start opening in late February thru April; reportedly survived -23 °F in southeast Pennsylvania, unusual for C. japonica.

Simple growing tips: camellia culture is similar to that of rhododendrons or azaleas. They prefer a mildly acidic well-drained, compost rich soil. Grow them in full morning sunlight in zone 6 and 7-a and in partial all day sun in zone 7b and points further south. Protect camellias against prevailing winds, particularly in the winter months. Irrigate new plants in their first year, but do not overwater. Mulch with an acidic type leaf mold from oak leaves or pine bark chips or nuggets; mulch feeds and protect roots from drastic heat and droughty soils.

Avoiding Slug Problems On Hostas

Posted by Hugh on September 6th, 2016

Slug injury on hosta

Finding slug resistance among hosta varieties is relative. By late summer, you will find some holes in leaves in almost every variety, some a lot worst than others. There are ways to reduce slug injury in your host plantings.

Weather is a key factor. Wet summers means higher slug and snail populations. Dry summers is the opposite. They hide and multiply in a moist environment containing plenty of dead or decaying leaf and twig debris on the ground.

Good garden sanitation is important in reducing slug damage. Keep hosta beds free of weeds, fallen leaves and other wastes. Mulches and decaying foliage make an ideal slug haven. Cut your hostas back to ground level when foliage dies back late in autumn. Compost plant wastes away from hosta plantings..

During extended dry periods, irrigate hostas deeply but not frequently. Excess watering causes attracts snails and slugs. If you’re not watering sufficiently, plant leaf edges and tips will turn brown.

Hand-pick slugs from your hostas and nearby plants. Slugs are nocturnal feeders. Deposit them in a “kill jar” containing isopropyl alcohol or soapy water.

Make your own slug trap. Set shallow containers such as empty margarine and cream cheese containers are perfect. Filled containers with beer at dusk. Sorry, but fresh beer does attract more slugs than stale beer. Space traps 4-6 feet apart around hostas and other susceptible plants. Slugs will crawl into the bowls overnight and drown.

Hosta varieties with heavier and textured leaves are generally more slug resistant. Some examples include:

‘Abiqua Drinking Gourd’

‘Big Daddy’

‘Blue Mammoth’

‘Blue Plate Special’

‘Blue Shadows’

‘Blue Umbrellas’

‘Bright Lights’

‘Camelot’

‘Frances Williams’

‘Halcyon’

‘Krossa Regal’

‘June’

‘Love Pat’

‘Regal Splendor’

‘Sagae’

‘Spilt Milk’

‘Sum and Substance’

‘Tokudama’

The bottom line: Plant hosta varieties with thick or heavily textured leaves. Be ready to use slug bait or create your own bait trap. Slug baits are readily available from garden centers. Non-chemical alternatives are also effective. Most bait products contain metaldehyde. It is highly toxic by inhalation, moderately toxic by ingestion and may cause skin and eye irritation. It is poisonous on birds and other wildlife, including household pets.

Leaf Retention In Landscape Trees

Posted by Hugh on September 2nd, 2016

Leaf retention of American Beech

Beech in Tennessee Woodlands

Most deciduous landscape trees drop their leaves sometime in autumn. The physiology of autumn leaf drop is primarily stimulated by changes in photoperiod or shorter daylength. Autumn colors develop and the leaf petioles form an abscission layer. Black gum (Nyssa sylvatica), for example, start to color up in early September.

Winter leaf retention by deciduous trees is termed “marcescence”. Some hardwood trees, particularly Beech (Fagus spp.) and oak (Quercus spp.) trees, retain their leaves through the winter months in Northeastern U.S. Oaks and beeches are in the Fagaceae family. Additional species include witch hazel (Hamamelis spp.), hornbeam (Carpinus spp.), and hophornbeam (Ostrya virginina).

Most (not all) oaks and beeches begin shedding old leaves the latter days of February. Plant scientists speculate that retained leaves may deter browsing animals such as deer. The dried leaves may help to protect dormant buds or make them difficult to nibble on. Dried leaves are likely less nutritious.

Most years Japanese maple (Acer palmatum) have shed their leaves by late November. Some cultivars may be slow to shed their foliage, and are caught in an early hard frost. Leaves turn brown and hang on for several weeks, sometimes for months. Dissected leaf varieties are more affected compared to palmate types. Fine textured dissected-leaf cultivars, like ‘Tamukeyama’ and ‘Waterfall’, often retain their brown withered foliage until early March.

Young and newly planted landscape trees tend to retain leaves their first year after planting. Fruit trees, specifically apple and pear trees, are in a juvenile stage.

But not to worry. High winds, snow loads, and rains in winter, in addition to swelling of vegetative buds in the spring causes marcescent leaves to fall to the ground.

Pest Alert: Viburnum Leaf Beetle May Be Invading

Posted by Hugh on August 30th, 2016

Arrowwood viburnum (V. dentatum) Is Highly Susceptible

Viburnum-leaf-beetle (photo from Michigan State University)

Viburnum Leaf Beetle is gradually coming to the Southeastern U.S. It was first found in upstate New York in 1996. This pest has been on the move, eating its way through native viburnums from upstate New York to northern Pennsylvania to western Maryland.

It feeds only on viburnum species. Preferred species include native arrowwood viburnum (V. dentatum), European cranberrybush viburnum (V. opulus), American cranberrybush viburnum (V. trilobum), and Rafinesque viburnum (V. rafinesquianum). Other viburnums that also serve as hosts include Sargent viburnum (V. sargentii), wayfaringtree viburnum (V. lantana), nannyberry viburnum (V. lentago), and blackhaw viburnum (V. prunifolium).

This insect overwinters as clusters of eggs inside pencil-sized twigs, essentially killing these small twigs on edge of branches. Affected shrubs leaf out from lower buds and infest new pencil-sized shoots in spring. The larvae skeletonize the leaves and can completely defoliate plants by mid-June. Larvae drop off the shrubs, pupate and emerge as adults.

From July through September the adults do minor feeding, lay eggs and repeat the cycle. Each year viburnums decline from repeated infestations and die after 3 to 5 years of defoliation and egg-laying damage. Viburnum beetle is pretty easy to kill with insecticides containing either pyrethroid, carbaryl, or acephate (Orthene®), targeting larvae and adult stages. Unfortunately, spray applications of pesticides do not protect shrubs from egg-laying adults that may fly in from untreated areas during July through September.

Another treatment approach is to inject or drench the soil around the susceptible shrub with imidacloprid (Merit® or Bayer Advanced Garden Insecticide®) in late fall. This will protect shrubs from the larval feeding in the spring.

According to Research Entomologists at Michigan State University, these viburnum species are highly resistant: Koreanspice viburnum (V. carlesii), Burkwood viburnum (V. burkwoodii), doublefile viburnum (V. plicatum var. tomentosum), Judd viburnum (V. x juddii), lantanaphyllum viburnum (V. x rhytidiphylloides), and leatherleaf viburnum (V. rhytidiphyllum).

‘Furman’s Red’ Sage For Long Blooming Period

Posted by Hugh on August 28th, 2016

Salvia ‘Furman’s Red’

Texas sage (Salvia greggii) is a low bushy native perennial or woody shrub. It is native to Texas south to Mexico and varieties come in white, red and purple. It has proven to be exceptionally cold hardy (USDA hardiness zones 5b-9).

Furman’s Red sage is a superior cultivar here in the Southern Appalachian region.Flowering is best in spring, less so in summer, and finishes with a superb show in the fall.

Furman’s Red salvia demands sunlight (6 hours minimum) and a well drained garden soil. It tolerates a wide range of soils, wanting only good drainage. Feed a slow release fertilizer such as Osmocote® or Nutricote® at planting time or in early spring. An alternative fertilizing plan is to apply Miracle-Gro®, or Schultz® every 4-6 weeks according to package directions.

Plants grow upwards of 3 feet tall and 2 feet wide. From late spring, summer and early fall, this long-flowering salvia is topped with bright red two-lipped flowers. Leaves are soft green. Foliage is mostly deciduous, but foliage remains green over mild winters in zone 6 Tennessee.

Tidy up old plants in early spring and cut back in summer to stimulate a second flush of flowers. Follow a regular watering schedule in the first growing season to develop a deep, extensive root system. Added irrigation encourages repeat blooming in hot dry summers.

The minty fragrance of the flowers attracts hummingbirds, butterflies and bees. Texas sage is deer and rabbit resistant.

Furman’s Red salvia is a 2005 Plant Select Winner. Available is limited to on-line native plant nurseries such as High Country Gardens in New Mexico (mailing address 2438 Shelburne Road Suite 1, Shelburne, VT 05482).

Late Summer Bulbous Beauties – Spider Lily and Fall Crocus

Posted by Hugh on August 26th, 2016

Spider Lily Pops Up in Weedy Lawn

Colchicum (fall crocus)

Spider lilies (Lycoris radiata) go by a number of colloquial names including resurrection flower, surprise lily, and naked ladies. Naked 1-2 foot tall flower scapes bear 4-6 bright coral-red flowers. Each 2- inch long flower exhibit reflexed tepals and long protruding stamens resembling spider legs (common name “spider lilies”).

Almost overnight, the leafless flower spikes arise in late summer. Several weeks later, strap-like gray-green leaves arise where the floral stalks had been and have now disappeared. Foliage stays evergreen through the winter to feed the below ground bulbs before dying back in spring.

Plant bulbs 9 -12 inches apart in late spring or early fall. Plant them shallow with the neck of the bulb just peaking through the ground. Plants will naturalize by bulb-offsets and form small colonies over time in the southeastern U. S. (USDA hardiness zones 6-10).

Autumn crocus (Colchicum autumnale) is native to Great Britain and Ireland (USDA hardiness zones 4-7). Colchicums bloom in the earliest days of fall often coming up in late August. In late spring, plants send up 4-6 dark green lance-shaped leaves, some which 10- 14 inches long. The foliage yellows and dies down by summer into dormancy. Flower stems with no leaves emerge from the ground to 4-6 inches tall in late summer to early fall bearing goblet-shaped 3 inch long flowers. Flower colors vary from purple to pink to lilac. Weak flower stems tend to flop.

Plant corms 3 inches deep and 6 inches apart in August for bloom that occurs in the same year and many years following. To move or expand an existing planting, mid- to late-summer in the best time.

Both Lycoris and Colchicum grow in organically rich, medium moisture, well-drained soils in full to partial sunlight. Plants respond negatively to soil moisture, preferring dry soils during the summer dormant season and moderate soil moisture during bloom period in late summer. Provide a minimum of 4-5 hours of sunlight for high flower count.

Colchicums (autumn crocus) are not be confused with the true autumn crocus or saffron crocus (Crocus sativus) that also bloom around the same time. The latter are edible and closely related to the spring-flowering crocuses. All plant parts of colchicum are highly poisonous

Neither lycoris or colchicums have serious insect or disease problems. In a wet summer slugs and snails may become significant troublesome pests.

“Plant It Pink” Planting Program

Posted by Hugh on August 23rd, 2016

Invincibelle Spirit ll Hydrangea

Invincibelle Spirit ll (photo provided by Proven Winners)

To build awareness and show support for those affected by breast cancer, over 40 volunteers filled public gardens and surrounding areas with pink plants in downtown Haslett, a suburb of Lansing, MI. The Invincibelle® Spirit II hydrangeas are a beautiful reminder that we are not alone in our hopes and prayers for a cure.

With one in eight women facing a breast cancer diagnosis in their lifetime, Proven Winners® ColorChoice® supports the Breast Cancer Research Foundation (BCRF). BCRF is the highest rated breast cancer organization in the U.S. and provides critical funding for cancer research worldwide to fuel advances in tumor biology, genetics, prevention, treatment, metastasis and survivorship. Since 2009, over $903,000 has been raised for BCRF through plant sales and Pink Day fundraisers hosted by independent garden centers across the United States and Canada.

This donation effort continues the legacy of giving one dollar($) from each plant sold to BCRF. Invincibelle® Spirit II (Hydrangea arborescens ‘Invincibelle Spirit ll’) is a 2015 introduction. It is an improvement upon the original Invincibelle® Spirit, from the breeding work of Dr. Tom Ranney at the North Carolina Research and Extension Center at Mills River, NC. Invincibelle Spirit ll hydrangea has brighter flower color, stronger stems, and superior container presentation. It is also a reliable re-bloomer that sparkles in gardens from Manitoba to Mobile.

Simple Growing Information: Smooth hydrangea (H. arborescens) is a loosely branched deciduous shrub that grows to 3 – 6 feet tall and wide (USDA hardiness zones 3-9). This native species is easy to grow in average, moisture, well-drained soil in partial sun to shade. Invincibelle® Spirit hydrangea series grows more compact at 3 – 4 feet in height and width. It flowers on new wood from late spring thru early summer. Prune this hydrangea after the main flowering period has finished. Irrigate shrub(s) during dry periods to keep summer foliage looking fresh.

Credit: sales data on Invincibelle Spirit II hydrangea provided by Mark Osgerby, Spring Meadow Nursery, Inc. in Grand Haven, Michigan. Photos provided by Proven Winners.

Seeding Shady Areas Of Your Property

Posted by Hugh on August 21st, 2016

Shady Patch of Lawn

How many times have you been told: “you can’t grow lawn grass in shady areas”. Most lawn grasses perform best in full sunlight. Red or chewings fescues (Festuca rubra) perform under as little as 2-3 hours of direct or dappled sunlight.

Shade fescues are relatively easy to maintain. Mowing height should be 2 inches high in spring and fall and 2 ½ inches in summer. They do not require much fertilizer. Red fescues tolerate winter cold temperatures, but are less drought and heat tolerant than tall fescues. They also resent heavy foot traffic.

Fertilize shade fescue lawns at least twice annually – March or April and again in September or October. When starting a new seeding, use 3-4 lbs. seed/1000 sq. ft. rate.

Preparing new ground: rototill to a depth of 4-6 inches. Have a soil test performed at least 4-6 weeks prior to seeding to accurately determine how much lime (or gypsum) and fertilizer to apply. If the soil has not been tested in 3 or more years, apply a complete lawn fertilizer (contains N, P, and K) according to recommended rate on the package. Evenly rake fertilizer and organic amendments into soil and eliminate soil ruts.

Evenly disburse (sow) grass seed according to recommended package seeding rates. Lightly rake the seed into the soil ⅛ inch deep. Keep the area watered daily (if no rainfall) until seeds have germinated (usually in 10-14 days) and the seedlings have grown sufficiently to establish a lawn.

Extra step prior to seeding: if the site is excessively weedy, mow the area and apply a non-selective herbicide such as glyphosate (Roundup™).

Covering Bare Spots: Mow lawn closely, rake up cut grass, leaves, stones, sticks and other debris. Sow seed in bare areas by hand, fertilize and add soil amendments as needed. Seeding rate is 1-2 lbs per 1000 square feet.