Pruning Basics


Late February/early March is the perfect time to prune in your garden.  The goal is to complete pruning before new growth begins in the spring.   Pruning will be stressful on plants, so avoid the period during bud break and leaf expansion in spring so plants can use their stored food during this period of activity.  This is true for summer flowering trees and shrubs and most evergreen shrubs.  Spring flowering shrubs  (in general) are best pruned after they bloom.  There are many reasons we need to prune in our gardens including to maintain size & aesthetics, for plant health, and to encourage flowering.

Most plants can be pruned year round for aesthetic reasons and for general shaping. The three basic pruning techniques for shrubs are heading back- for size control where individual branches are shortened, thinning which is to remove an entire branch back to main trunk, and shearing used to clip foundation shrubs such as hollies.  When pruning most plants, you may ask how much should I prune back? In general, the one-third rule is a good guide. By not taking out more than one-third of a plant at a time, you will not over stress the plant.  If you need to reduce a plant by more than half its size, then now is the optimum time to do this before new growth begins to emerge. Avoid severe pruning other times of year as it may be too stressful and the plant may not recover.  Remember that slower growing plants such as Boxwoods and Osmanthus may not fully leaf out as quickly sometimes taking the full growing season to recover. On the flip side  many broadleaf evergreens benefit from severe pruning. The easy rule of thumb to remember is that the faster and larger a shrub grows the more you can cut it back and the better it will recover.  Sometimes a plant out grows the space where it is planted, so don’t be afraid to remove a plant to avoid extreme pruning maintenance and perhaps replace with a more appropriate sized plant.  

Pruning for plant health involves the three “D’s” of pruning-  Dead, Diseased, or Damaged.  These types of branches should be cut out any time of year.  Pruning to allow more light and air circulation in the canopy will help reduce insect and disease problems.  

Pruning to promote flowering can be a bit tricky.  Some plants bloom on “new wood” and others on “old wood”.  Flowering on new wood means that a plant does not create flower buds until after growth begins in spring and this new growth will produce the flower buds.  Plants that flower on new wood typically flower in late spring, summer and fall. Some examples of plants that flower on new wood include roses, Hydrangea paniculata & arborescens, hibiscus, abelia, beautyberry (Callicarpa), roses, ligustrum, nandina, crape myrtle, and butterfly bush (Buddleia).

In North Carolina, most early spring blooming shrubs (there are some exceptions) flower on old wood and are best pruned after they bloom so that you do not inhibit their spring show of flowers.  Flowering on old wood means that a plant forms the flower buds for next year’s blooms during the current year.  Prune these plants immediately after blooming.  Some examples of plants that flower on old wood include forsythia, azaleas,  winter jasmine, styrax, viburnum, spirea, weigela, calycanthus, oakleaf hydrangea, and climbing hydrangea.  If you prune before they flower, you’ll remove the flower buds. If you wait too long after they’ve finished blooming, they may not have enough time to create flower buds for next year.

Bigleaf  or lacecap hydrangea  (Hydrangea macrophylla) is the plant that throws a wrench into all of the typical advice about pruning, because it flowers in late summer on old wood. The best advice on pruning big-leaf hydrangea is to avoid doing so if at all possible, because you cannot prune it without sacrificing some flowers. Even in the case of re-blooming hydrangeas like Endless Summer, which flowers on both old and new wood, avoiding pruning ensures the longest display. If you’ve inherited an older type of hydrangea, or moved to a home with a large hydrangea reduce it by one-third of the stems every year after flowering until you get it to the height you desire.

Shrubs that flower on old wood and offer ornamental fruit cannot be pruned without sacrificing their display, so it is best to avoid pruning these all together:  Winterberry holly (Ilex verticillata), Blue holly (Ilex x meservae), Viburnums  - if grown for the berry display.  Don’t forget to prune old growth off perennials, liriope and other ornamental grasses in late winter/early spring to make way for new spring growth.   

I hope these tips and techniques will make pruning in your garden easier, so sharpen up your pruning tools and get to work quickly!  

Crazy About Conifers

 When most plants have gone bare or underground for the cooler months, dwarf conifers offer winter interest to the garden through their multitude of shapes & sizes, amazing textures and terrific colors.  This is a great time of year to take note of your garden and find areas that need more "bones" or year round substance.  Dwarf conifers are a great solution to creating this structure.  Conifers can be used as accents or focal points as well as incorporated into mass plantings. Most conifers prefer well-drained soil and sunny locations, with the exceptions Taxus and Chamaecyparis, which are two genera that tolerate some shade. Don't bank on dwarf conifers only for winter interest because this unusual group of plants bolster many attributes all year long. Colors and textures abound in the world of conifers, so let me share some of my favorites with you and I will categorize them by color. 


  One conifer I continually use over and over in part shade to full shade conditions is the Dwarf Garden Plum Yew (Cephalotaxus harringtonii 'Prostrata').  This is a sprawling plant with glossy needles that makes a handsome groundcover in dry areas.  It grows to about 2’ tall x 4’ wide in size.   Cryptomerias have become a favorite evergreen screening plant of the south, but let's look at some of the dwarf Cryptomerias available.  Cryptomeria japonica 'Globosa Nana' forms a soft, meatball shape of bright green that requires no pruning.  This is a wonderful plant to use flanking steps, walks or entry ways, growing to 4' tall x 4' wide in ten years.  'Black Dragon' is a narrower, upright form with dark green foliage that makes a more sculptural statement.  This slow growing Cryptomeria grows 10' tall x 3-4' wide.  'Gyokuryu' is a more vigorous cultivar of Cryptomeria that forms a dense, broad pyramidal shape with bright green foliage. It grows to 8-10’ tall and 4-6’ wide.   Dwarf Hinoki Cypress (Chamaecyparis obtusa ‘Nana Gracilis’) is a compact, slow-growing, loosely pyramidal form that acts as a superb specimen at a front entry or next to a patio or seating area.  Maturing to a size of only 6' tall x 3-4' wide in fifteen years. Thuja occidentalis 'Mr. Bowling Ball' is a low growing arborvitae with soft, blue-green foliage and has a very compact, oval form.  It grows 3-4' tall x 3-4' wide making it a great accent plant or container plant.  Dwarf Garden Juniper (Juniperus conferta 'Procumbens Nana') is a wonderful low-growing juniper forming a dense mound of branches that radiate from the center.  It is bright green in summer and turns more bluish green as it matures, making a nice addition to a rocky slope or rock garden.


The blue and silver colors offered by conifers is not found among any other woody plants.  Grey Owl Juniper (Juniperus virginiana 'Grey Owl') and Angelica Blue (Juniperus chinensis 'Angelica Blue') are two of my favorite medium shrubs offering shimmering blue foliage and graceful, arching branches.  Both are wonderful when paired with red berries and burgundy foliage.  For low-growing groundcover try Juniperus horizontalis 'Wiltonii' (Blue Rug) or J. horizontalis 'Blue Chip (Blue Chip).   These are tough, drought tolerant spreaders with steel blue foliage and an added bonus of having a purplish tint through winter months.  One of my favorite conifers is Cedrus deodara 'Feeling Blue'.  This is a compact, weeping form of Deodar Cedar that has a soft, fine texture and makes for a most spectacular specimen growing to just 2' tall x 6' wide.  Feeling Blue looks great when planted to creep over a large boulder.  We can't forget the Dwarf Blue Spruce (Picea pungens f. glauca) such as 'Fat Albert' & 'Baby Blue Eyes,' both noted for their dense, upright pyramidal shape that reaches 10-12' tall x 7-8' wide and having steel blue needles. If you are looking for a very dramatic focal point, then try the Weeping Blue Atlas Cedar (Cedrus atlantica ‘Glauca Pendula’).  This special conifer naturally grows with a sprawling horizontal habit and has icy blue needles.  Often it is trained into an upright weeping form that creates a dramatic yet graceful, waterfall-like effect.


Plants with yellow foliage may be a bit harder to incorporate into the landscape, but these golden beauties definitely offer bold color and contrast.  Probably one the most used dwarf conifers is the Golden Threadleaf Cypress (Chamaecyparis psifera 'Filifera Aurea'). This drooping shrub with fine, vibrant yellow foliage has an interesting weeping habit much like a shaggy haircut.  Chamaecyparis obtusa 'Verdoni' is also a nice compact pyramidal plant that sports yellow foliage and grows 5-6' tall x 3-4' wide.  Gold Coast Juniper (Juniperus pfitzeriana ‘Aurea Improved’) has been around a long time and for good reason.  This evergreen shrub that grows 3' tall x 4' wide is noted for its arching branches of intense yellow foliage especially pronounced during the winter months.  Thuja occidentalis 'Franky Boy' is another dwarf conifer having an upright form that I love for its thread-like golden foliage that turns bronze-orange in winter and lemon-yellow in spring.  It matures to 4' tall x 3' wide. A note to remember is that most yellow foliage conifers will turn green in shade so be sure to provide enough sun to keep the foliage bright.

My list could go on and on of wonderful dwarf conifers to add to your garden.  Whether incorporating dwarf conifers as focal points, flanking walkways or steps, or mixed into borders & foundation plantings, you will be pleased with the intense color, interesting textures and unique shapes they offer to your garden.