Mugo Pine

60608‘Shrubbery’ sounds so unflattering for a pine; but mugo pine, Pinus mugo, is not really much of a tree. The tallest trees do not reach eaves. Most old trees are only a few feet tall and about twice as broad, with strictly rounded form, and dense forest green foliage. The stout paired needles are only about one or two inches long. The plump cones, which are rarely seen, are not much longer.

Although very rare in other types of landscapes, and originally from the Austrian and Italian Alps, mugo pine is one of the most popular and traditional features in Japanese gardens. Even though it grows very slowly, it should have enough room to do so without competing with other more aggressive plants that might overwhelm it. It should neither be shorn nor pruned back too aggressively.



60316As a shorn evergreen hedge or simple shorn shrubbery, photinia, Photinia X fraseri, produces handsomely glossy bronzy red foliage without bloom. It is best if shorn as weather warms at the end of winter, and then allowed to grow out for a while. It can be shorn again through summer as bronzy foliage fades to green, but should not be shorn so often that it is always deprived of red foliage.

Without regular shearing, photinia becomes a small tree or large shrub. Trees can either be staked on single trunks, or allowed to develop multiple trunks. New growth in spring is not as vigorous as it would be in response to shearing, so is not as colorful. Domed trusses of tiny white flowers bloom about as soon as new foliage appears. The floral fragrance can be objectionable to some.

Only the biggest and oldest trees reach high voltage cables. Most stay less than fifteen feet tall and broad. Hedges can be kept less than six feet tall, and ideally, should be kept less than half as deep (from front to back). Photinia can grow rather well while young, but then grows slower as it matures. Partial shade or a lack of water through summer compromise foliar color and density.

‘Little Ollie’ Olive

60302Those of us who appreciate olive trees for their fruit production or distinctively gnarly trunks probably would not understand the popularity of the Little Ollie olive, Olea europaea ‘Little Ollie’. Not only is is completely fruitless, but it lacks sculptural trunks and limbs. It is instead a short and and shrubby plant that gets only about three or four feet tall, with very dense grayish green foliage. Only the narrow evergreen leaves are recognizable as those of an olive tree.

Little Ollie olive behaves something like boxwood, and does not grow much faster. It can even be shorn as a hedge or topiary. It is quite resilient to heat and harsh exposure, and once established, it does not need much water. Because it is so compact, and has such resilient roots, it is popularly grown in large urns or planters. The grayish foliage is a nice backdrop for more colorful annuals and flowering perennials.

Boulevard Cypress

51230Between New England and the Pacific Northwest, the boulevard cypress, Chamaecyparis pisifera ‘Cyano-viridis’, is classified as a small tree, even though it gets no bigger than large shrubbery. Locally, only very mature specimens reach the eaves, without getting much more than half as broad. Trunks and limbs remain concealed by fluffy evergreen foliage. Warm and dry air limit growth.

The handsome foliage is strikingly silvery blue, comparable to that of Colorado blue spruce or blue Arizona cypress, but with a surprisingly soft texture. It is really quite distinct from other evergreens, even other closely related chamaecyparis.

Boulevard cypress prefers cooler climates, so does well locally in light shade sheltered from wind. During warm weather, it can get roasted if too exposed. Although it does not require much water when mature, it is happiest if watered somewhat regularly.

Laurel-Leaf Snailseed

80926The first half of the name sound appealing enough. The second half, not so much. Do the seeds grow into snails? Do they just look like snails? Not many have seen them. Tiny pale white flowers that are supposed to bloom in spring, as well as small black berries that develop after bloom, are rare. Laurel-leaf snailseed, Cocculus laurifolius, is grown just for its glossy evergreen foliage.

The foliage superficially resembles that of common privets. Upon closer inspection, the leaves are somewhat elongated, and outfitted with distinct marginal veins flanking the midveins. As stems that become heavy with lush foliage lean over, vigorously vertical stems fill in the space, until they too arch over as they become fluffy with foliage. Mature trees might get twenty feet high and wide.

Because of its complaisant roots and tolerance of partial shade, laurel-leaf snailseed is popularly installed as a foundation plant (at the foundation of a home) but then obscures windows as it gets too big and awkward. Its arching branch structured does not do well with formal shearing. It works much better as an informal screen in the background, or as small tree with multiple trunks.

Glossy Abelia

50916With indiscriminate pruning, glossy abelia, Abelia X grandiflora, will never develop its natural form, with elegantly long and thin stems that arch gracefully outward. Sadly, almost all get shorn into tight shrubbery or hedges that rarely bloom. If only old stems get selectively pruned out as they get replaced by fresh new stems, mature shrubs can get eight feet tall and twelve feet wide.

Against their bronzy green foliage, the tiny pale pink flowers that bloom all summer have a rustic appeal. In abundance, they can be slightly fragrant. The tiny leaves are not much more than an inch long. Vigorous young canes that shoot nearly straight out from the roots slowly bend from the weight of their bloom and foliage as they mature.

Partial shade is not a problem for glossy abelia, but will inhibit bloom somewhat. Young plants want to be watered regularly. Old plants are not nearly so demanding, and can survive with notably less water. If alternating canes is too much work to restore old and neglected plants, all stems can be cut back to the ground at the end of winter. New growth develops quickly.

New Canes Replace Old Canes

50916thumbHeavenly bamboo, or simply ‘nandina’, is one of those many plants that almost never performs like it should. The intricately lacy foliage is so appealing while plants are young, and changes color with the seasons. The red berries can be comparable to those of holly. Unfortunately, healthy plants grow, and then ultimately get shorn into globs of disfigured leaves and stems.

The same abuse afflicts Oregon grape (mahonia), mock orange (philadelphus), forsythia, lilac, abelia and all sorts of shrubby plants that really should be pruned with more discretion. Their deteriorating older stems should be pruned to the ground as new stems grow up from the roots to replace them. It is actually not as complicated as it seems.

This pruning process, known as ‘alternating canes’, prunes the plants from below. It is a standard pruning technique for maximizing production of blackberries, raspberries and elderberries. It is similar to grooming old stalks from bamboo and giant reed, even if it does not prevent them from spreading laterally.

The deteriorating older stems, or ‘canes’, are easy to distinguish from newer growth. Old canes of Heavenly bamboo and Oregon grape become heavy on top, and flop away from the rest of the foliage. Old canes of mock orange and lilac get gnarled and less prolific with bloom. Aging abelia and forsythia canes become thickets of crowded twigs.

The newer stems are likely a bit lower, but are not so overgrown. Since the foliage is not so crowded, it is displayed on the stems better. Their blooms or berries are more abundant. By the time new growth becomes old growth, there will be more newer growth right below it. In fact, the regular removal of aging canes stimulates growth of new canes.

This is the time to prune Heavenly bamboo and Oregon grape, just because the oldest foliage is as bad as it will get after the warmth of summer. Mock orange, forsythia and lilac should get pruned while dormant through winter, but are commonly pruned just after they finish bloom early in spring. Abelia should probably wait until spring because new growth can look sad through winter.

Overgrown Shrubbery Becomes Small Trees

80530thumbThose of us with ‘maintenance gardeners’ are likely aware of how rare it is to find someone who knows how to maintain hedges properly. It seemed so simple years ago. Several identical plants could simply be planted in a row, and then somewhat regularly shorn for confinement to a prescribed space. They were not allowed to exceed a specific height or width for long between shearing.

Formal hedges are now passe. They do not conform to modern landscape style. No one wants to maintain their formality anyway. If a gap develops, it is likely to be filled with a different cultivar or species that is not identical to the rest of the hedge, merely because it happened to be available at the nursery. Feral or invading shrubs, vines or even trees get shorn right into the whole mess.

Then there is the problem with bloat. Rather than staying confined, hedges typically get slightly larger with each shearing. What is worst is that most of the extra bulk is high up and shading lower growth, causing it to grow slower. Hedges eventually develop that all too familiar top-heavy appearance, and encroach into otherwise usable space that they were designed to provide privacy for.

There are few simple options for hedges and shorn shrubbery that have gotten too big for their space. Some can be renovated and cut back beyond their outer surfaces, but recovery will take a bit of time, and can not fix unmatched plants. However, such restoration is likely better than replacement. Just like for a new hedge, feral and invading vegetation must be removed in the process.

Another option is to completely change the form of improperly shorn shrubbery to small trees. This can be done with individual shrubs, or a few selected remnants of an otherwise removed hedge. Cherry laurel, photinia, bottlebrush, tea tree, privet, various pittosporums and many other large hedge shrubs work quite nicely. Rather than getting pruned back into submission, the lower growth gets pruned away to expose sculptural trunks within, and the upper growth gets pruned only for clearance above.

Jumping Juniper!

P80519KOh, the stigma of juniper never gets old! No matter how many cool new cultivars get introduced, and how many specie get rediscovered, they are still though of as those nastily prickly ‘tams’ that were too common in the 1950s. Even some of us who really like junipers dislike tams, not only because they share their stigma with all other members of the genus, but also because they really are nasty and prickly, and not as useful as their overuse would suggest. Are they deep ground cover or shallow shrubbery? They might work for a few years, or maybe many years, but they eventually crash into each other or other plants and pile up into a dense thicket that can not be pruned without being deprived of all dignity.

In the neighborhood where I primarily work, we have a ‘do not plant’ list. Such lists typically cite specie that are notoriously invasive, such as pampas grass, blue gum eucalyptus, Acacia dealbata and English ivy. In regions where fire is a concern, specie that are notoriously combustible, such as cedar, cypress, rosemary and manzanita, are also cited. Almost all of the specie on our list are there for good reason. I mean, we can figure out why they are undesirable in the neighborhood. Then there is juniper. No specie are cited; just the entire genus. Juniper.

Perhaps the eastern red cedar, Juniperus virginiana, is too likely to become an invasive exotic here, so the entire species was condemned. Perhaps junipers in abundance are just too combustible. The ‘do not plant’ list provides no explanation.

There are a few mature junipers in the landscapes that were installed before the list was compiled. A hedge of such junipers was recently removed because it was in the construction zone of buildings being renovated. It was no loss really. They were quite disfigured after decades of reliable service. However, at one end of the hedge, there were two much younger junipers that were added relatively recently to replace one that had been removed to facilitate access to subterranean utilities. They might have been added after the ‘do not plant list’ was compiled. No one really remembers. The list was compiled a few years ago, but distributed only recently.

Before the landscape was demolished, we took a few plants that could be dug up, and canned them back at the nursery for use elsewhere in other landscaped areas. We could not just leave the two small junipers to die. We dug and canned them too. Now they are back in the nursery, with no hope of finding a home back in the landscape from which they came. They happen to be nice specimens, and are certainly NOT tams. No one remembers what species or cultivar they are. They happened to match the original hedge remarkably well, which is rather impressive considering how modern cultivars have replaced most older cultivars.

I happen to have three canned junipers already. They are North American natives. Two are eastern red cedar, Juniperus virginiana, with two very distinct personalities. The other is the Juniperus communis ‘Compressa’, which is a compact cultivar and the closest I could get to the common juniper. Apparently, the common juniper is not so common in the natural form. I already do not know what to do with these three, although the common juniper can stay canned indefinitely.

These other two displaced junipers will probably go into a landscape pretty soon, while they are not yet root-bound. They just can not go any place close to where they came from.

Sweet Pea Shrub

70111It may not always bloom profusely, but sweet pea shrub, Polygala fruticosa, blooms sporadically through most of the year. Even when not much color is evident from a distance, a few flowers can likely be found on closer inspection. For some reason, bloom seems to be quite colorful now. Bloom phases should be more profuse in spring and summer. The pea flowers are soft purplish pink.

Mature plants might only get to two or three feet tall and wide, but have the potential to get larger. They are usually a bit wider than tall, with a nice rounded compact form. The evergreen foliage is slightly grayish light green. Sweet pea shrub prefers full sun exposure, but can get roasted in hot spots. A bit of shade should not be a problem. Once established, it does not need too much water.