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

Don’t Crawl /Let’em Weep White Pine

Posted by Hugh on January 15th, 2012

4-foot Young Weeping White Pine

Pinus strobus 'Pendula'

In the beginning was a small weeping pine which wanted to crawl along the ground because it had no “legs”. The gardener came along and straightened up the leader and attached it to a tall pole. Straightening and staking continued for several years. Many years later it grew into a tall weeping white pine (Pinus strobus ‘Pendula’).

The leader and branch shoots pf white pine emerge in late April. The 3 – 5 inch long needles have fully elongated by early June in the Southern Appalachian region (USDA zones 6 and 7). Staking is best performed anytime from mid to late June. The shoots become semi-woody, yet are still flexible.

The main shoot (leader) is bent vertically upward and tied to the stake. The staking and tying procedure is neither complicated nor time consuming. Use soft jute or cotton twine, and not wire twist-ems® or plastic ties for fastening to the stake or a trellis. After 6-8 months, loosen the ties so they won’t girdle the tender main shoot (leader).

At planting position a sturdy 12-16 foot metal or heavy duty plastic stake close to the trunk. White pine grows 12-18 inches per year. On rare occasions a tree may produce multiple leaders. Remove all but the one you want to continue up the stake. Within 8-10 years, your weeping white pine should support itself on its strong straight leader and the stake may be permanently removed.

‘Little King’ Birch For Small Gardens

Posted by Hugh on January 12th, 2012

'Little King' River Birch at Daniel Stowe Bot. Garden in NC

Little King, aka Fox Valley™, (Betula nigra ‘Little King’) is a 10-12 foot tall shrubby river birch, which fits into small landscapes. Simple minimal pruning can shape it into a lovely small tree. Little King possesses the desirable traits of large river birches, including an oft-white exfoliating bark.

River birch exhibits good heat tolerance in the Southeastern U.S. (USDA zones 4-8) and has fewer disease and pest problems than other birches (Betula spp.). Locate a diminutive ‘Little King’ adjacent to a deck or patio where it can easily viewed by family and guests. Add landscape lighting to highlight ‘Little King’ either in the garden or from inside your home any time of the year.

Grow it in full or partial sunlight (6-hours sunlight recommended). River birch is native to moist river bottom lands, and is not fussy about soil type. Soil pH should be slightly acidic to avoid pale green or chlorotic foliage in late summer from iron or manganese deficiency.

Availability is limited to specialty nurseries on the internet or through special ordering at your local nursery/garden center. It has been available since 1991 and more wholesale nurseries are growing it.

What Can Be Done About Phytophthora

Posted by Hugh on January 10th, 2012

Phytophthora disease (Phytophthora spp.) is the fatal cause of root rots, stem cankers and crown rots. Several hundred species of plants are susceptible, including redbuds, dogwoods, rhododendrons, camellias, white pines, firs, yews (Taxus spp.), and fruit trees. It thrives in warm moist saturated soils. Phytophthora may lie dormant in the soil for several years, waiting for a susceptible host plant and ideal environmental conditions.

Some common symptoms include yellow-green foliage, wilting, dead branches, and whole plant death. Infected leaves typically turn various shades of brown, die, and remain on the branches for several months.

Your best approach is to avoid the disease completely. Purchase only healthy trees and shrubs. Inspect the root ball for size dimension (compare to the top) and look for visible damage. Leave sick plants at the garden center.

Avoid plant stress by selecting the proper planting site. For example, most needle evergreens grow best in full sun, while broadleaf rhododendrons prefer partial sun. All demand a well-drained soil, preferably situated on a slight grade or slope. Do not plant in heavy clay or compacted poorly drained ground.

Prior to planting, remove all nylon and plastic burlap and twine around the root ball. Jute or cotton burlap and rope may be left around the rootball. Set most shrubs and trees at the same depth (as at the nursery). Fertilize plants in late winter at the proper amounts; overfeeding may worsen Phytophthora root rot infections. Water the plant(s) on site within three days after planting. Apply 2-3 inches of an organic mulch around the tree and do not pile mulch up around the trunk.

Once Phytophthora has been diagnosed, apply treatments of Subdue MAXX™ or Aliette™ fungicides in the spring and fall to prevent further disease spread. Fungicide treatments are quite expensive and removal of the sickly plant may be your best option.

Phalaenopsis Orchids Easy To Grow

Posted by Hugh on January 8th, 2012

Moth Orchids (Phalaenopsis) easy to grow

At one time, growing orchids was a hobby that only rich doctors, lawyers and fictional detectives could afford. Today, the very affordable “moth orchids” (Phalaenopsis spp.) are commonly available at supermarkets and big hardware chain stores at reasonable prices. They’re easy to grow and produce large showy flowers which bloom for two or more months.

Moth orchids can spend most of the spring and summer months outdoors beneath the dense leafy canopy of a shade tree. They come back indoors in early fall here in the Southern Appalachian region (USDA zones 6 and 7).

The winter season in most home is a tough environment for growing orchids. Orchids are plant epiphytes which grow on tree trunks and branches in the humid tropics. Their thick fleshy roots draw moisture from the air and various surfaces around the roots. Orchids are comfortable in home temperatures between 60 and 80 °F., but low room humidity is hostile to orchids. Room humidity as low as 10% is commonplace during the winter.

The bathroom and kitchen are the most humid rooms in the home, but outdoor light is usually limited. Moth orchids crave bright light but not direct sunlight. Sunlight intensity is weak and daylength is short in the Northern hemisphere between November through February.

Orchids are planted in special potting mixes containing coarse bark, sphagnum peat moss and perlite. Some mixes add charcoal for added drainage and to filter impurities. A good orchid potting mix should retain moisture for only a few days as their fleshy roots easily rot if the growing media is saturated for many days. Never leave a potted moth orchid standing in water.

Fertilize spring thru fall weekly with a high phosphorus based soluble house plant fertilizer. However, package directions are too strong for orchids. Use only half the amount recommended and feed weekly. Orchids are fertilized once monthly from December thru February. After repotting, do not fertilize for 2-3 weeks.

Get Past The Winter Blahs With Paperwhite Narcissus

Posted by Hugh on January 4th, 2012

A wonderful, easy indoor gardening project this winter is to start a dish (pot) of paperwhite narcissus (Narcissus tazetta). Paperwhites make a lovely white centerpiece on your dining table. Paperwhite bulbs are outdoor hardy in USDA hardiness zones 8 – 10. Store the bulbs in a warm dry location such as on top of a refrigerator until you’re ready to plant them. Never allow the bulbs to freeze.

Fill a shallow container about 80% full with a porous sandy potting soil mix similar to planting cacti and succulents into. Set the bulbs a few inches apart on top of the soil and add coarse sand or colored aquarium gravel to the top of the container. Set the bowl or pot in a sunny house window until flowering begins.

Generally, the blooms may be forced in 3-4 weeks inside a warm sunny greenhouse. Begin by forcing bulbs in a cool room (or outdoors on mild days) at 50-60 degrees to stimulate root growth. As buds swell and open, move the pot to a cooler spot out of direct light to extend the life of the flowers. Floral life average 7-10 days.

The small trumpet shaped flowers are pure white and exude a strong sweet fragrance. Flower buds may “blast” (never open) if too hot and low humidity inside your home. Plant height varies from 1-2 feet depending on available light and temperature inside the room. Fewer hours of light per day means taller flowers and a greater need for staking. Rotate the container every few days to keep floral shoots growing straight.

You may purchase bulbs at many full-service local garden centers and Brent and Becky’s Bulbs on-line.

Volcano Mulching Harmful

Posted by Hugh on January 1st, 2012

Mulch Piled Up Around Tree

Piling up mulch around trees or shrubs, called “volcano mulching”, is a bad practice and is killing them. Perhaps you’ve seen a neighbor or a professional landscaper doing it, and assumed that it must be alright. It’s not!

The deep mulch pile smothers the natural buttress flair of the trunk which breathes and absorbs air for the rootsystem. The sugary sap underneath the thin bark skin is a food source for harmful insects which overwinter in the mulch piled around the bark. It also becomes a haven for critters, particularly rabbits and field mice.

Organic-based mulches aid to conserve soil moisture, moderate soil temperature extremes and reduce competition from weeds. It also keeps mowers and string weeders (“weed wackers”) away from potentially damaging the tree trunk.

Mulch depth is recommended at 2-3 inches and is distributed around the tree in the form of a donut. The bulk of the mulch should lay 3 or more inches away from the trunk and taper off near the tree’s dripline (outer extent of branches). Excessive depth of the mulch also promotes shallow rooting by reducing oxygen to the roots. Trees become more susceptible to prolonged periods of drought.

Organic mulches include pine bark, hardwood bark, chopped leaves, pine needles, and composted grass clippings.

Grow And Re-bloom Christmas Cactus

Posted by Hugh on December 28th, 2011

Thanksgiving cactus

Holiday cacti, aka Thanksgiving cactus (Schlumbergera truncata) and Christmas cactus (S. x buckleyi ), are popular houseplants which grow (and re-bloom)for many years with good care. Christmas cactus has rounded (scalloped) stem segments while Thanksgiving cactus has 2-4 pointed teeth paired along each segment edge. The latter blooms 3-4 weeks earlier than Christmas cactus and is available in several colors. Holiday cacti are actually tropical epiphytes (like orchids) and not true cacti.

Holiday cacti bloom when exposed daily to uninterrupted 12-hour dark periods over 6-8 weeks starting in late September. A dark closet is a good place to do this. They also bloom when exposed to cool temperatures between 50 to 55 °F regardless of dark exposures.

Flower buds may drop prematurely due any of four factors: 1. over-watering, 2. low room humidity, 3. dry potting soil, and 4. insufficient light. Do not place a plant near a cold or warm draft such as a heating vent or poorly insulated window in your home.

Holiday cacti produce more blooms under bright light. Site your plants in a sunny window indoors, or beneath a shade tree in the summer garden. Leaf edges may redden or burn when exposed to excessive light.

When blooming in the fall and early winter holiday cacti are kept moderately dry and not fertilized. Water and fertilize in spring and summer when actively growing with houseplant-type fertilizer such as Miracle-Gro™, Peters®, Hollytone® or Schultz®. Follow the label directions. In March or early April holiday cacti are to encourage better branching before new spring growth begins.

Before the start of spring, repot the plant into a slightly larger container containing a well-drained sterile houseplant potting mix.

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Foster Holly Has It All

Posted by Hugh on December 25th, 2011

Bountiful Fruit Crop on Foster Holly

Foster holly (Ilex x attenuata) is an old holly favorite which has not lost its sizzle. While many new holly cultivars have entered the landscape scene, do not assume that Foster holly is now passé. It is utilized in a number of landscape options in the Southern Appalachian region (USDA zones 6 and 7), including in containers in zones 7 and 8.

Originally, there were five selections of Foster holly introduced by E. E. Foster of Foster Nursery, Bessemer, AL in the 1940’s. Still the most popular today is ‘Foster #2’, a female clone which produces a bounty of small bright red holly berries. Fruits continue to be effective throughout the winter. ‘Foster #4’ is its male pollinator mate, but in most locales, male American hollies (Ilex opaca) will also pollinate Foster #2.

Holly (Ilex spp.) grows in a moderately acidic (pH 5.8 – 6.5), well-drained soil and in full to partial sunlight. Feed with a water-soluble acidic fertilizer such as Miracle –Gro™, Miracid™, or Hollytone®.

Foster hollies display a strong vertical accent when utilized as specimen or foundation shrubs in front of tall buildings or on the corners of residences. They form a 12–20-foot dense evergreen privacy screen and may be sheared as hedges. Tall overgrown Foster hollies may be cutback severely in early spring for a small compact size. Heavy clipping can transform them into almost any topiary shape that you desire.

New Poinsettia Varieties Make Your Holidays Bright

Posted by Hugh on December 23rd, 2011

'Shimmer Surprise'

'Miro' poinsettia

Poinsettia is a gift which keeps on giving. Many gardeners save and nurture their plant to re-bloom again over the next winter holiday season. By early February the plant has likely dropped most of its bottom leaves and flower bracts. Cut back the bare stems by two-thirds and don’t be concerned about the oozing white sap. Care for the poinsettia as a house plant (watering and fertilizing) and provide light from a home window with eastern or southern exposure.

In mid to late March repot into a container, 1 – 1 ½ times larger. Move the plant outdoors on warm spring days when temps are above 50°F and back indoors on cool nights. The plant will spend most of the spring and all summer outdoors where it will easily double or triple in size with a regular watering and fertilizing. Cutback the shoot tips once or twice during the summer to increase branching.

In early fall, your poinsettia moves back indoors on cool evenings (below 50°F) and kept isolated in a room which is not lighted in the evening hours. Poinsettia requires 6 weeks of uninterrupted 12- hour nights to initiate flowers and colorful bracts. The plant receives adequate light during the daytime hours and watering and feeding continues.

By mid-November, small flower buds form and the upper leaves (bracts) begin to color up and increase in size. By the next winter holiday season your poinsettia will decorate your home once again.

'Winter Rose' poinsettia

Prickly Pear Is Easy Care

Posted by Hugh on December 17th, 2011

Prickly pear cactus (Opuntia)

There are over 200 species of prickly pear cactus (Opuntia spp.) worldwide. Several make great container plants in the garden or inside the home. Prickly pear cacti may grow to heights of 10 feet or more in the arid regions of the Southwestern U.S.

Eastern prickly pear (Opuntia compressa var. ‘humifusa’) grows 12- 18 inches tall and 30-36 inches wide. It will grow a bit larger in a warm moist habitat. The reddish “pear” fruits ripen in the fall. They taste like kiwi fruits and can be made into jam and jelly. The 3-4 inch wide bright yellow cactus flowers bloom in early summer in the Southern Appalachian region (USDA zones 6 and 7).

Prickly pears need a well-drained soil, preferably sandy or gravely, and they’re planted in full sun. Irrigation and fertilizing are rarely needed. Overwatering causes pads to collapse and the root system to rot. Cacti plants may appear wilted after a cold winter, but perk up and become fully turgid by early spring.

They are easily propagated from pad sections directly into the garden or a container. Allow the cut end to air dry (heal over) for 5-7 days before setting, cut end down, to a 2-inch depth into garden or potting soil. Moisten the soil after planting and no further watering is needed. Pad(s) generally root in 4-6 weeks.

Prickly pear spines greet you with hostility. Wear thick heavy duty gloves to protect yourself from the large smooth spines and small, hair-like needle spines over the pads.

Don’t Crawl /Let’em Weep White Pine

‘Little King’ Birch For Small Gardens

What Can Be Done About Phytophthora

Phalaenopsis Orchids Easy To Grow

Get Past The Winter Blahs With Paperwhite Narcissus

Volcano Mulching Harmful

Grow And Re-bloom Christmas Cactus

Foster Holly Has It All

New Poinsettia Varieties Make Your Holidays Bright

Prickly Pear Is Easy Care

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