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

Baptisias – Long-Lived Native Perennials

Posted by Hugh on March 10th, 2018

‘Carolina Moonlight’ baptisia

‘Purple Smoke’ baptisia at Mt Cuba Center, Greenville, DE

Wild indigos or Baptisias (Baptisia spp.) are long-lived native perennials. Baptisias are tap rooted perennials that will reward you for many years. They’re sometimes mistaken for Carolina lupine (Thermopsis caroliniana).

Modern day cultivars are hybrids of 4 Baptisia species: purple (B. australis), lavender blue (B. minor), white (B. alba), bright yellow (B. sphaerocarpa). Several bicolors are also available. Baptisias bloom for 3 to 4 weeks. Their blue-gray foliage and sturdy upright shrubby habit are pluses in the summer garden.

Baptisias perform at their best in full sun. In the shade they bloom less and stems are weak and frequently require staking. Baptisias prefer a deep humus-rich well-drained soil, but tolerate average soil. Mulch with organic matter to keep the soil cool and weed-free.

Vigorous plants grow 3 to 4 feet high and 4 to 5 feet wide after 3 to 5 years. Do not overcrowd. Newly planted baptisias should be watered until established, usually within 1-2 year. Plants are slow to establish and begin blooming, usually a few flowers in their first year and are covered with flowers in 3 to 4 years.

In early spring add 1-2 handfuls of a slow-release fertilizer around plants. Older well established plants require little to no fertilizer as they produce their own nitrogen. Yellowing of leaves in the summer is a symptom of iron deficiency or high soil pH. In such cases, feed with chelated iron or a water-soluble fertilizer such as Schultz™ or Miracid™. Established plants are heat and drought tolerant and are almost invincible to disease and insect problems.

Stunning stalks of colorful pea-like flowers appear in mid-spring. Flowers stalks give way to black seedpods by late July. Gardeners may opt to remove the seed pods before they mature. Flower arrangers utilize the ripe blacken seedpods in arrangements.

Cultivars with the deeper shades of blue and yellow blooms stand out in a garden. Popular cultivars include: ‘Purple Smoke’ (lavender flowers), ‘Solar Flare’ (yellow), ‘Alba’ (white), and ‘Twilight Prairie Blues’.

Tips On Repotting Container Plants

Posted by Hugh on March 7th, 2018

Canna in container

Banana (Musa) in container in Fort Worth Gardens

Eventually, all potted plants outgrow their containers. This includes potted roses, Japanese maples and other small trees, shrubs, dwarf conifers, elephant ears (Colocasia, Alocasia), cannas, lotus, papyrus, and lots more. A rule of thumb is to transplant every 2 years in early spring before bud break. In the case of perennials and tropicals, this is a good opportunity to divide plants. Tropicals may need to be set back into a greenhouse until it is safe to move outdoors.

Plants tend to deplete the soil of nutrients and soil pH may change. Select a container large enough to provide adequate space for plant roots, one that is one or two sizes larger. New soil media should be well-drained and retain moisture. Add a one inch deep layer of coarse to medium sized gravel or other rocks in the bottom of the container for extra drainage.

Spread out plant roots and fill in around the roots with the remaining soil media. Press down firmly, but do not injure roots. For grafted plants such as roses, Japanese maples, or certain conifers, don’t bury the bud union. Settle the soil (media) in the container and finish filling to within 1 inch of the lip of the pot.

The container may be plastic or clay. During hot weather clay containers provide a cooler soil environment for roots compared to plastic pots. Clay pots usually dry out faster than plastic. Choose light colored pots so dark shades heat up faster. Thin plastic and clay pots may crack during freezing winters.

Set the container in a location with adequate light and good air circulation. Allow 2 feet or more space between containers for adequate sunlight and proper air movement. For example, roses should have 6-7 hours of direct sunlight. Don’t crowd plants too close together as this may create a favorable environment for disease and insect troubles.

Ten Grow Facts About Perennials

Posted by Hugh on March 4th, 2018

Daylilies

Before purchasing and planting perennials, here are ten helpful tips to assist you in garden planning:

Perennials die back to the ground in fall or winter and regrow from plant crowns or roots the following spring.
Most perennials should be divided when they are dormant: Spring bloomers in the fall and Fall bloomers in the spring. Some (Shasta daisies, coneflowers, black eyed Susans) may need dividing every 3 years; hostas and daylilies every 5 years.
Perennials from cool temperate regions must undergo a cold winter to encourage new buds to grow in spring. Examples: asters, irises, lupines, wallflowers, peonies, and primroses,
Many perennials spread from underground roots (termed “rhizomatous”) which send up new stems in spring. Examples: bleeding heart, iris, coreopsis.
Some perennials, such as lupines, columbines and delphiniums are short-lived, lasting only 2-3 years in zone 6 and south.
Perennials are not totally maintenance-free. Some do clean up easier than others.
Deadheading, the practice of removing the old spent flowers often results in additional flowering 4-5 weeks later. Examples include beebalm (Monarda), blanket flower (Gaillardia), speedwell (Veronica), yarrow (Achillea), Shasta daisies (Leucanthemum), and many more.
Grand expectations: most perennials do not reach their full potential (size and flower numbers) until 3-4 years after planting. Many gardeners say “first they sleep, year 2 they creep, year three they leep”.
Most perennials bloom in a specific timeline. Reblooming daylily and iris cultivars flower 2-3 weeks in summer and re-bloom again in fall (with extra care). Select lots of different kinds to lengthen the blooming cycle in your garden. Since perennial bloom is periodical, interplant with lots of colorful longer flowering annuals.
Some perennial species may be invasive in your state. Check with your state’s Department of Agriculture or Natural Resources to find which plants are listed as invasive.

Why No Fruit On My Tree?

Posted by Hugh on March 1st, 2018

Espaliered apple tree

Why trees fail to bear fruit or only produce fruit every other year? There are 8 common reasons:

Excessive Tree Vigor – Primary cause is over-fertilizing and/or over-pruning fruit trees. Heavy applications of nitrogen will stimulate excessive growth at the expense of flower production. A nearby fertilized lawn may supply too much nitrogen to adjacent fruit trees. Heavy winter pruning also stimulate excessive growth. Apple and pear trees are pruned differently than peach, plum, and cherry trees.
Frost Damage – Late spring frosts or temps below 30 °F will damage flower parts. Do not plant fruit trees in low land areas. Fruit trees bloom at different times in the spring. Early flowering apricots are frequently damaged by spring frosts. Peaches bloom first before cherries, plums, pears, peaches and apples (last). Apple varieties flower at different times, such as Gala and MacIntosh bloom before Rome Beauty.
Severity of winter temperatures. Extremes in temperatures over winter months can damage dormant flower buds. Areas where winter temperatures consistently drop below -15 °F will not support consistent fruit production. Flower bud hardiness (most hardy to least cold hardy): Pears > Apple > Apricots > Tart Cherries > Sweet Cherries > Plums > Peaches > Nectarines.
Poor Pollination by Bees – Weather factors like rain or high winds will reduce bee activity and pollination. Improper spraying of pesticides will also reduce bee populations. Avoid the use of insecticides during bloom that may kill honeybees.
Cross vs Self-Pollinated – Apples, pears and sour cherries must be cross pollinated for maximum fruit crops. Plant 2 or more different varieties for optimum fruit set. Peaches, nectarines, tart cherries and most plums are self-fruitful and only one variety is necessary to produce fruit.
Over-production – Heavy crops the previous year, particularly apple and pear trees, can reduce shoot growth and/or prevent flower formation. Remove some fruits by hand within one month after petal fall. With apples and pears, thin to 1 to 2 fruit cluster per 6 to 10 inches of branch length. Heavy crop loads on peach and nectarine trees reduce shoot growth and less fruit buds will form the following year. With peaches and nectarines, thin to one fruit per 10 inches.
Tree age – Apples and pears should not bear fruits until 3-4 years after planting (depending on rootstock). For example, apple varieties are grafted on semi-dwarf rootstock like M111 or EM7.
Sevin™ (Carbaryl), sprayed on apple and pear trees when they’re flowering or within first month after petal fall, will cause some or all fruits to drop. Read the label of pesticides to avoid unintentional thinning of the fruit.

Fifteen Garden Perennials Which You Can’t Kill (Or Almost)

Posted by Hugh on February 26th, 2018

Herbaceous peony

Daylily

Here is a list of flowering perennials that need little care after planting. Ornamental grasses and ferns are not listed here. One steadfast rule that you must follow if this group of plants are to work for you: “choose the right plant for the right site”. Shady plants in full sun and terrestrial plants in swampy ground are no-nos. If these plants are properly planted, all should prosper.

In most locations (zones 5-7), they’re long-lived and are disease and insect free. Many (except where indicated) flowering perennials prefer full sun and humus-rich well-drained soil.

The list:

Italian arum (Arum italicum) – bright variegated foliage arise in fall and grow through winter; red cluster berry fruits appearing in late spring; partial to full shade.

Baptisia or wild indigo (Baptisia spp.) – full sun; purple, blue, yellow or white flowers appear in mid-spring.

Coreopsis (Coreopsis spp.) – full sun and moderate soil moisture; many cultivars including single-, semi-, or double- petalled yellow flowers bloom in late spring thru summer if deadheaded.

Lenten rose (Helleborus x hybrida) – many great cultivars to choose from; partial shade; mid-to late winter flowering.

Catmint (Nepeta x faassenii) – several great cultivars including ‘Walker’s Low’ and ‘Six Hills Giant’; spring-summer flowering.

Cranesbill, hardy geranium (Geranium spp.) – lots of great cultivar choices available; partial shade; spring flowering, popular cultivar ‘Rozanne’ blooms intermittently from late spring to autumn.

Chinese astilbe (Astilbe chinensis) – many cultivars; easier to grow compared to A. x arendsii; morning sun; late spring-early summer blooming.

Fairy Wings, barrenworts (Epimedium spp) – excellent ground cover ; early spring flowers; deciduous or evergreen varieties available; partial to full shade.

Siberian iris (Iris sibirica) – green, black and variegated foliage and numerous flower colors; full sun.

Daylilies (Hemerocallis x) – over 70.00 varieties to choose from. Select those suited to your regional location; shop at a daylily grower in your locale.

Peony (Paeonia officinalis) – hundreds of great cultivar choices available; full to partial sun; mid-spring flowering.

Russian sage (Perovskia atriplicifolia) – full sun; mid-summer and later bloomer; several new dwarf or compact growing cultivars such as ‘Denim and Lace’, ‘Little Spire’, ‘Filigran’.

Variegated Solomon seal (Polygonatum odoratum ‘Variegatum’) – bright variegated foliage, flowering is secondary; partial shade.

Tall sedums (Sedum x spectabile) – several cultivars; full sun; summer flowering.

Lilytuft, Monkeygrass (Liriope muscari) – part to full sun; many cultivars including with dark green ‘Big Blue’, striped ‘Variegata), and chartreuse (‘Peedee Ingot’); clumps 8-12 inches high; Spike-like clusters of pale violet to white flowers in mid to late summer.

Understanding How To Purchase Nursery Stock

Posted by Hugh on February 23rd, 2018

Large b&b Tree ready for shipping

Covered nursery stock ready for shipping

Nursery growers supply trees and shrubs to garden centers in any of five ways:

Container Grown – Plants have been growing in a container or pot for one or more growing years. Some plants have been grown in containers or they were field dug and repotted into containers. These transplants are not likely to experience transplant shock. Before planting, take a few minutes to “tease” the outer roots, particularly if they are pot bound or over crowded.

Field Dug To Containers – Many plants are dug out and placed into pots to be put on display for sale at the nurseries. When dug out, they are either dug with soil or moved bare-root. The question is: how long have they been growing in the pot since being moved from the field; six months or a year is ideal, but sometimes it may be one month or less. Many are potted in spring and then immediately shipped to the store. Often the roots have not acclimated to the new soil or the root balls have been damaged. Essentially you are buying a bare-root transplant, potting mix and the container. Some nurseries have “root pruned” the plant to fit into its new container size.

Balled And Burlapped (b&b)- The tree or shrub is dug from the field by hand or by a tree digger (laborer) along with the soil. The root ball is wrapped in burlap and jute (never nylon) twine. Many of the fine feeder roots are lost in digging. A b&b tree will usually survive transplanting if purchased and planted in late winter thru mid-spring. The tree may still be susceptible to transplant shock. Obtain a one-year money-back guarantee from the nursery or garden center.

Bare Root – Some trees and shrubs can be successfully transplanted without any soil on the roots. The trees are fully dormant, either in late fall or very early spring. In early spring roses, fruit trees, raspberries, grapes, and blueberries are sold this way. Once the leaf buds have emerged in spring, the chances of a successful transplant quickly falls off. Bare root plants should be planted immediately into your landscape. When these plants are on sale in late April and May, it’s best to pass them up. Obtain a money-back guarantee from the nursery or garden center selling bare root plants.

Machine-Dug – Professional landscapers dig and move large trees from a nursery field or private property with a mechanical tree spade to a new planting site. The success of this technique is fully dependent on how much of the root ball can be moved intact. Larger nursery grown trees experience severe transplant shock.

Select A Good Street Or Landscape Tree

Posted by Hugh on February 20th, 2018

‘Happidaze’ sweetgum on Median Strip In Johnson City, TN

‘Sango Kaku’ Japanese maple for sale at Samara Farms Nursery near Nashville, TN

First of all, there is no perfect tree, either for a street or landscape planting. However, many excellent cultivars are now available at local nurseries and retail garden centers. Select one that matches your site requirements. Site factors include: amount of sunlight daily, soil type, soil pH (acidity or alkalinity), and soil drainage.

What kind of tree do you want -shade, flowering, privacy? Will it fit size-wise into the landscape? Avoid fast growing trees like silver maples (Acer saccharinum), Siberian elms (Ulmus pumila), cottonwoods and poplars (Populus spp.), walnuts (Juglans spp.), and willows (Salix spp.) that are susceptible to storm damage and are short-lived. They may also be hosts to insect and diseases and drop messy fruits or seeds. Does the site have height limitations (look up for power lines) and enough for root growth. Are roots shallow such as maples, some oak species, or elms which may uplift sidewalks in a few years.

A good shade or street tree is a long-term investment. Start by purchasing a high-quality plant. Trees 8 to 10 feet tall, either balled and burlapped (B&B) or growing in containers, are usually the best buy. Species that are difficult to transplant may be more easily to establish if you start with a smaller size. The tree may even come with a guarantee with free replacement.

Where to find good reliable information regarding the best tree to plant? Check at your local Extension office or land grant university. They will usually list the most reliable tree for your region. Many independent garden centers stock these recommended cultivars. Additionally, search for plant sales at a local botanical garden and arboretum.

Trees are listed in three size groups according their size. Large trees reach a mature height greater than 60 feet. Medium-sized trees grow to 30 and 60 feet. Small trees (less than 30 feet tall) may be also classified as flowering or ornamental trees such as crape myrtles, redbuds, crabapples, dogwoods (Cornus spp.), and Japanese maples; over the years they mature into a handsome small shade tree.

Winter Blooming Winter Jessamine

Posted by Hugh on February 17th, 2018

Gelsemium sempervirens ‘Butterscotch’ at Atlanta Botanical Garden

Bright yellow tubular flowers of jessamine

Carolina jessamine (Gelsemium sempervirens) is one of the most beautiful native vines in the South (USDA Zones 6 to 9). In February and March, its bright yellow flowers are commonly seen growing along roadsides in the Southeastern U.S. It is frequently mistaken for forsythias a shrub that rarely blooms in winter.

Vines grow vigorously, 20 feet or more if not pruned. Gardeners may choose to rein a jessamine into a 3-4 foot tall shrubby vine covering only 3-5 square feet of ground. Its annual growth rate is 12-15 inches in average soil and no irrigation and a lot more aggressively in rich soil and adequate watering.

From February to April, sweetly scented golden yellow flowers blanket the cascading, fine textured foliage. The tubular 1 to 1½ inches long blooms are 5 lobed. Flowers invite early arriving butterflies and bumblebees into your garden. Glossy 1 to 3 inches long leaves are evergreen.

Carolina jessamine is easy to grow. Plant it on a trellis (arbor), in a container on a deck and patio or as a ground cover along steep banks erosion control.

Carolina jessamine tolerates either full to partial sunlight. Flowering is more prolific and foliage is denser in full sun. Moist well-drained soil is ideal. Jessamine can withstand periods of drought once established after one year. Ground cover plants should be spaced 3 feet and 5- 8 feet apart as a trellis.

Fertilize while the plant is actively growing with moderate amounts of a slow-release fertilizer such as Osmocote™ or Nutricote™. Do not over-fertilize as it may reduce flowering.

In containers jessamine may require pruning 2-3 times annually to hold growth in check. Many gardeners utilize a string pruner for this task. Old, sickly or out of control vines can be pruned back to a few feet above ground level after flowering. Remove all dead or broken branches.

Popular Cultivars:

‘Pride of Augusta’ – popular double-flowered cultivar with long bloom period; also listed as ‘Plena’.

‘Margarita’ – slightly larger flowers and is rated cold hardier than species.

‘Woodlander’s Pale Yellow’ – large creamy-yellow but is rated as not as cold hardy (Zone 8 -10).

Butterscotch™ – blooms 2 to 3 weeks later than species and often re-blooms in fall.

Lemon Drop™ – more compact with shrub-like habit and with light yellow flowers.

All parts of the plant are highly poisonous. The sap may cause skin irritation. Insects or diseases are rarely a problem on Carolina jessamine. Deer and rabbits will not eat it. Carolina jessamine is the state flower of South Carolina.

Seven Step Care Tips For Container Roses

Posted by Hugh on February 14th, 2018

Highlt Rated ‘Flower Carpet Pink’ Rose

‘Doris Day’ floribunda

You can grow beautiful roses in containers on your patio or deck. All you need is an adequate container size and a growing area with plenty of sunlight. The life of container roses is short,usually 2-3 years. Each spring, plants should be transplanted every year into a new container. Container size is very important. Follow these 7 steps:

Choose the right rose. Fragrant, compact, disease-resistant varieties with continuous blooming perform best. Smaller rose types- miniature, floribunda, and some hybrid teas work the best. Compact Flower Carpet™ roses are an excellent size for small containers for 3-5 gallon containers. Also try the Carefree™, Oso-Easy™, and Home Run™ series.
Pick the right pot. Anything with a drainage hole(s) will work. It should be deep enough as roses have long, deep root systems; aim for a depth and diameter of 15 inches or more. 1/2 barrels are a great choice.
Plant into a quality potting mix and enrich with compost to increase water holding capacity.
Water containers regularly so that media (soil) stays moist, but not sopping wet. If your rose container dries out in less than two days, it may be potbound or the container is too small to support its roots.
Feed every 4 to 6 weeks with a water soluble fertilizer such as Miracle-Gro™ or Jacks™ for more blooms. In colder zones, stop fertilizing 8 weeks prior to first frost. Add 1-2 teaspoons of Epsom salt (Magnesium sulfate) 2-3 times during the growing season.
Keep your rose(s) pruned: (a) deadhead, (b) size and shape, and (c) control insects and disease.
Re-pot every 1-2 years to refresh the soil. Transplant into a larger container if you observe a decrease in blooms.

Warning: thin plastic and clay pots may crack during freezing winters. In northern regions (Zones 3-6), winter protection of the tender roots is an absolute must.

Get An Early Start On Spring With Dawn Viburnum

Posted by Hugh on February 10th, 2018

Viburnum bodnantense ‘Dawn’ at NC Arboretum in Asheville, NC

Summer foliage (labelled ‘Pink Dawn’)

Viburnum x bodnantense (cross between V. farreri and V. grandiflorum) is a hybrid viburnum that was developed at Bodnant Garden in Wales in 1934-1935 (USDA zones 5-9). Also called Pink Dawn, this shrub is cherished for exceptional three-season interest – fragrant pink flowers in spring, clean, blemish-free summer foliage, and above average fall color.

‘Dawn’ is a cultivar that features rosy-pink flowers. The shrub grows upright in a multi-stemmed, vase shaped habit. It typically matures to 8-10 feet tall and 4-6 feet wide. Toothed, 2-4 inch long narrow-ovate leaves emerge in spring with bronze tints on leaf edges; leaves mature to deep green hues. Foliage turns an attractive burgundy-red in fall. Flowers give way to red berries (drupes) that ripen to black in the fall.

Its showy flowering habit is reason enough to plant this early flowering viburnum, in many years blooming alongside winter-flowering winterhazels (Corylopsis), fragrant honeysuckle (Lonicera fragrantissima) and paperbush (Edgeworthia). In zone 6, the reddish buds swell and open into the clusters of long-lasting, clear pink, tubular flowers. Summer foliage is dark green and branches are cinnamon colored.

Dawn viburnum grows in average, medium moisture, well-drained, moderately acidic soil in full sun to partial shade. Expect greater numbers of flowers in full sun and less so in shady landscape areas. Avoid soils that are droughty or soppy wet. Site the shrub in a protected location to help protect spring flowers to hard freezes. Fertilize and mulch shrub(s) in early spring. Prune the shrub immediately after spring flowering is over.

Dawn viburnum may be planted as a foundation or plant several for a hedge or privacy screen. Cultivar named ‘Charles Lamont’ grows 1-2 feet taller but is not as wide. All other traits similar to ‘Dawn’.

Habit is upright-spreading with stiff, coarse branching. Grows 10-12′ tall and about 2/3 as wide. Flowers are slightly larger and a brighter pink than ‘Dawn’ and have yellow anthers. Flowers at a very young age and thought to be more free flowering. The leaves are also larger than that of ‘Dawn’.

No serious insect or disease problems trouble this shrub viburnum. Late winter/early spring flowers are susceptible to frost damage.

Dawn viburnum has received the Royal Horticultural Society Award Of Merit.