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The John A. Sibley Horticultural Center

Sadly Missed

botanical gardens, horticulture, horticultural centerSwiftly and silently, the powers that be decided to close one of the greatest horticultural displays in the United States. Sibley Center is no more. Callaway Gardens has shifted priorities from horticulture and floral beauty to resort and golf. That is the way with wonderful gardens. They simply cannot last during prolonged recessions. I am so happy I was able to spend a lot of time there when my children were young, so they could see ornamental horticulture done on a grand scale.

Sibley opened in 1984 as part of an expansion inside Callaway Gardens in Pine Mountain, GA. It was designed by Robert E. Marvin and Associates to be a showcase of energy-efficient blending of indoors and out, with folding walls that could be open during warm weather and could close to protect vegetation from extreme cold. 

About Shrubs

professional plant advice, sage leafI am a plant nerd. My fascination started at summer camps and state parks, touring woodland wildflower trails with experts on edible natives and shady stream ephemerals. In college I was motivated to study landscape architecture after being inspired by Mary Wharton, my professor and author of A Guide to the Wildflowers & Ferns of Kentucky and Trees & Shrubs of Kentucky, books I still refer to today. During my landscape architecture internship, Michael Dirr’s Manual of Woody Landscape Plants: Their Identification, Ornamental Characteristics, Culture, Propagation and Uses was the essential reference in the landscape industry, and I read it cover to cover. It was such a privilege to hear so many great plant experts speak, and even better to visit their home gardens.

My background is in landscape architecture with a strong emphasis on horticulture. I did a lot of industrial campus plans and municipal work before being hired to review landscape design plans for a state department of transportation, and I worked, early in my career, on large-scale planting and irrigation plans. I did lots of residential work, too. I got to know the green industry and gained practical experience in how to keep plants alive and maintain them. You get to know plant species after specifying several hundred of them on a single site!

I reviewed thousands of landscape plans, and also provided technical advice for anything related to landscapes, wrote contract specifications for planting and grassing, wrote maintenance specifications and work plans, and created statewide policies for roadside landscape projects and permits. I also helped create a statewide landscape grant program and vegetation management permit policy which provided ongoing funding for the program.

It has been great fun doing all this, but what good is it for a single person? I want to share the practical and experiential advice I learned with you. It takes a long time to become a professional landscape design and plant expert, because so much of what is realized comes from hearing the stories and experiences of in-the-field landscape industry professionals. I never read that the Red Maple species are much stronger in storms than its cultivars. I learned that while riding in a truck to a construction site with a seasoned landscape contractor. An owner of an industrial landscape maintenance company explained to me how sensitive Sweet Gums are to root disturbance. A garden club lady taught me not to prune back perennials with hollow stems in the fall to avoid rain rotting out the root system before spring growth could begin. Being a master gardener volunteer for many years gave me a wealth of information from agriculture extension, too.

What do I want to tell you about shrubs and ornamental plants?

• You have thousands of choices. Choose wisely and you will avoid lots of pruning later.

• Flowers provide color, but you can achieve longer-lasting interest and a more sophisticated landscape composition by using foliage color and textural contrast.

• You can use the tips and guidance on this web site to use plants to their fullest potential and create some amazing landscapes. It may seem simple to pick up a truck-load of container plants, walk around on a site with shovel in hand, and plant them.

The devil is in the details, though!

I want to share as much as I can with you about what I’ve learned over the years, but you can find detailed information in my Advanced Guide to Shrubs eBook, coming soon. I would love to hear your comments and about your roadside enhancement stories and experiences, too.

Advanced Guide to Shrubs, professional plant advice







You might also enjoy the Advanced Guide to Landscape Grants eBook, full of practical tips for applying for funding and making your beautification project a success.

Advanced Guide to Landscape Grants









Professional Pruning Techniques

Pruning Creates or Maintains a Shrub’s Natural Form

professional pruning techniquesTopiary is a delight. Controlling nature is an impressive show of power. Too much power corrupts, according to Lord Acton. I will paraphrase his famous words—Put down your electric shears.

Good pruning is like a good haircut. There are times when a dramatic, Avant guard, blunt cut is exciting, but most trimming should look natural. The best way to prune is to clip away anything that challenges a plant’s natural shape, and hide the cut deep within the remaining foliage. Limit the tortured, manipulated geometric shapes to theme parks and special display areas. Pruning shrubs into unnatural shapes brings decline, cuts off potential blooms, and is inappropriate for every setting (except a formal parterre garden).

Avoid the temptation to create green balls and trapezoids out of foundation evergreens. It’s tacky. I’ll leave it at that. Professional landscape designers create maintenance specifications that prohibit the use of electric shears for this very reason. Look at the excellent example of specialty shearing in the photograph. Everything tapers to a wider base, so sunlight can reach all the branches. This topiary menagerie has lasting quality because the professional pruning crew understands plant material.

A Midsummer's Floral Beauty

The Last Burst of Color before the Dog Days

summer bouquet, cutting back flowers in mid-summerThere can be two floral seasons in the summer if you put in some extra effort. The first typically ends the first week in July, just before the dog days of summer begin. If you can brave the heat and humidity to do a few maintenance tasks in the next couple of weeks, it will pay off with a second flush of color and floriferous-ness in late summer.

Step One—Cut back any spent blooms and any flowers that have peaked right away. Deadheading can wake up perennials by fooling them into thinking their primary directive for reproduction has not yet been completed. Allowing the older flower heads to go to seed will send plants into a lazy decline and the foliage will begin to suffer from pest damage while the stems will elongate and flop to the ground. Interrupt the circle of life by removing both the petals and the developing seed pods. Be thorough. Leaving behind any flower heads and seed pods will keep the plants complacent, thinking their job of reproducing a new generation is done.

Step two—Rejuvenate large masses of flowers in a wholesale manner by cutting back the entire plant by about one-fourth the total height. This will scare out fresh growth and result in densely branched stems ready to set new blooms. Shearing back herbaceous plants removes damaged foliage that harbors insects and disease.

Step three—Forget step two. Carefully trim each individual stem to get a more refined, aesthetic look. Giving them a haircut helps the appearance of the garden, and the results of the cut-back will be directly related to the care with which you wield your clippers.

There are a lot of plants that benefit from this tough love. Shrub Roses, Purple Coneflowers, Lobelias, Chrysanthemums, Geraniums, Yarrow, Baptisia, Salvias, Daisies, Butterfly Bush, Fennel, Cut and Come Again Zinnias, and Marigolds. Other plants won’t be fooled. Black-eyed Susans, Pennstemons, Iris, and Daylilies bloom once, and that’s it. They’re done for the season. Their charm is their fleeting nature.

You need to perform this cut back to keep your landscape looking manicured and refined. By late July, spending time outdoors for very long is too hot and too muggy for comfort, so take advantage of cool evenings and breezy days. It may seem wasteful to remove some blooms at their peak, but you can bring them inside for arrangements and enjoy them at close range in air-conditioned bliss.

Wait Until June

Patience Can Pay Off with a Nice Surprise

yucca color guard, frost damage, plant recoveryI was excited to see a side shoot developing on my Color Guard Yucca plant that acts as a focal point for the carport entrance drive. I had the perfect spot for the new baby plant, so in February, I carefully lifted the mother and sliced off the shoot for transplant. Things didn’t go as well as planned. Almost none of the original root system transferred to the new shoot, and the removal peeled away one side of the main stem. I thought I might have killed the original Yucca. I transplanted the new shoot anyway, with illogical optimism. The new division slowly began to deteriorate, and the stems eventually turned an unhealthy gray before rotting away.

I was excited to find a forgotten Fig tree growing in a shady area of the lower yard. It must have been sunny in that area long ago, but a nearby Holly shrub had grown twenty-five feet tall since then and the tree was struggling to survive. In November, I transplanted what was left of it to a nice, sunny area and gave it some lime, because Figs love lime in the soil. In the spring, after all the other shrubs put out new leaves, the little Fig had nothing but a few, bare stems.

And then, I waited. With experience, I knew how important it was to hold on to hope until the magic month of June. Just as we are deceived every year into thinking it is safe to plant tender annuals during the first warm weeks of spring, only to lose them to a late frost, we are deceived into thinking if we don’t see growth on a plant after all danger of frost is gone, a plant is dead. Not true! Well, not true some of the time. It is most definitely worth it to wait an extra month or two to see if a tiny sliver of hope and spark of a supernatural will-to-live is left in your lost-cause plants.

Awkward Moments in the Off-season

Bad Hair Days for Plants

bad hair day for hydrangea, off-season plants

Plants rarely look pretty all the time. There are off-season times when they look pretty… bad! There is usually a low point during the year for every plant. That’s why writers mention “seasonal interest” as an asset in the garden. During different seasons of the year, different plants will peak. The transient nature of gardens is part of their value to us. The off-season moments remind us of the fleeting beauty of all life.

When I lived in the North, the plant selections were based on cold-hardiness rather than clean shapes. If a plant could survive the harsh winters of Iowa, they earned a place in the limited list of options for landscape design. Precious evergreens were planted in double rows as windbreaks, and foundation plant beds were expected to be bare during the harsh winters. Cold-hardiness was a key requirement for every woody ornamental plant.

When I lived in the Midwest, large, deciduous, flowering shrub borders were the standard in every landscape. With attractive fencing as a backdrop, lots of flowering shrubs were lined up along property lines in long shrub borders. Conifers were often segregated into separate collections in their own display beds. Taxus held the foundation plantings together during the dormant season. The off-season for most plants was after spring flowering, when the shrub borders became plain-Jane plant growth—just messy tufts of uninteresting green.

Mid-Spring Celebrities

Seasonal Plant Syncing

mid-spring plantsMid -spring is the time for a flush of new seasonal growth for plants. For landscape professionals, the calls have started. The retail stores are in full-blown spring fever frenzy, selling anything that is blooming. The awareness of the plant activity around us intensifies the experience of energetic creation within us.

Intense foliage and flower color can be achieved with the right choice of plants. If you want a garden-tour-worthy display in mid-spring, search for deep, dark green leaves mingling with light, bright blooms and foliage. Dark green foliage is a perfect backdrop for spring combinations.

Evergreens, like Cephalotaxus harringtonia prostrata are sending out interesting chartreuse shoots of fresh foliage at the tips of emerald stems, strengthening the contrast of new and old growth. The fresh, tender growth of all the plants is fun to touch. It’s adds a softness to the landscape. The intense green is echoed by the low ground cover, Evergreen Candytuft (Iberis sempervirens), a reliable mid-spring stand-out. Instead of chartreuse, Evergreen Candytuft brightens the garden with pure, creamy-white buttons of bloom, almost covering the plant.

Early Spring

Seasonal Plant Sync

Easter plants, early spring plantsThere’s a moment, every year, when you realize that spring did arrive and life will go on. Consciously or subconsciously you are reassured that winter has been pushed away once again. It is the moment when the earth sprouts with chartreuse and lime yellow and pink and purple and white—the Easter colors.

By the time the early spring plants sync, it’s beyond time to do a lot of gardening musts, like pre-emergent herbicide applications and transplanting dormant and bare root plant material. No matter, because the euphoric effect of this color riot is just too cheerful and encouraging to slow you down. Everyone becomes a gardener for a few weeks, planting seeds and buying fertilizer. This is the time we put out new annuals that will be zapped by a late frost, because the hard freeze of the winter is long forgotten. Optimism is the norm. What a great time of the year

Ground Covers

The Connective Tissue of Landscape Compositions

ground covers, low shrubs, ivy growing in ferns

Ground Covers and facer plants complete the edge of a triple-level vegetative screen. They hide unsightly, leggy shrubs and define shrub bed borders. A ground cover is a mass of low plant material that acts to unify the ground plane and protect the bare soil, but it isn’t mowed or cultivated like turf.  Turf provides a walking surface.  A ground cover, in contrast, actually acts to discourage foot traffic and protect tender surface roots of nearby shrubs and trees.  Ground covers provide the finishing edge and unifying connection to the soil for a shrub bed.

Choosing ground cover species for a landscape setting is a complex task. It is important to know which ground covers grow in a uniform, dense mat, and which prefer spotty growth or small groups. The natural vegetation floor isn’t amenable to vast sweeps of uniform plant material.  The unaffected ground plane is a wild mix of multi-layered and diverse plants with a succession of growth and bloom and change.  Native ground covers and grasses prefer to grow in clumps rather than sweeps, and they welcome competition from neighboring volunteers.  The best choice is a tapestry of different low shrubs to fill in the ground plane as a living mulch and provide a definitive edge for plant beds.

Establishing a new ground cover bed often starts with the initial step of killing everything that is growing in the plot and covering the remaining soil with a layer of mulch to prevent new seedlings from trying to return. Avoid tilling near existing shrub and tree roots. Space new plants so they fill in thickly. Many ground covers can be propagated by division, which is great. You can establish new beds with inexpensive divisions from existing plants.

A ground cover planting often acts as a propagation bed for competition from weeds. The natural inclination for ecosystems is to cover and fill every spot of bare ground, and if weeds can grow into place first, they will. The assumption that a ground cover bed can be a self-sustaining, no-maintenance area is overly optimistic.  Natural equilibrium is the lazy gardener’s goal, but ground covers won’t stand for idleness.  The cooler the climate, the longer the wait for a full-grown ground cover bed, but the less work to keep it weed-free. Once established, most ground cover plantings need to be hand- weeded with vigilance and persistence.  Plant and then prepare for battle. Maintenance should focus on removing weeds quickly. Density of coverage determines how easy or difficult the weed patrol will be.

Space new plants so they fill in thickly and quickly. Small, herbaceous ground covers like Mondo Grass can be planted as closely as six inches apart in staggered rows. Herbaceous perennials and woody ground covers need to be one-and-a-half feet or less apart. Large coniferous woody ornamentals like Junipers can be spaced as much as two-and-a-half feet on center. Proper spacing is related to each type of plant, but keep plants as close as your budget and the species allow.