Interior courtyard planters, commonly designated as horticultural respites within bleak apartment complexes, or situated between more architecturally minded townhome or condominium units, are a challenge where plant selection is concerned.
Restricted light, excessive heat, impaired air circulation, wind tunnel effects, or a combination of the above may be experienced by courtyard plants.
Although exposed to the sky, courtyards may be surrounded by walls several stories tall with only a few hours of direct sun during the summer and little to zero direct sun during the winter. Yet where direct sun does manage to peek through, it may scorch plants due to heat reflected from white or buff-colored walkways or stucco building facades.
One distinct advantage of gardening in courtyard planters is demonstrated on cold winter nights. Cold that can damage or kill plants growing on the outside of courtyard walls is mitigated within these walls by hardscape surfaces such as brick and concrete that absorb heat during the day and radiate it out at night, to the advantage of nearby plants.
Low-growing tropical plants also benefit from overhanging stairwells, arches, patio covers and leaf cover from taller shrubs or trees since heat that radiates up from the ground at night is trapped and held in place by overhead structures or foliage.
In a meandering condo courtyard in Valley Village, I was witness to several botanical marvels courtesy of some unique microclimates created in variously exposed or protected planters.
I was most captivated by a large planting of chartreuse cymbidium orchids. Flower petals were clean and smooth, a departure from other cymbidiums I had seen planted outdoors over the years, whose flowers were generally pockmarked with tattered petal margins and yellowing leaves.
Clearly, these Valley Village cymbidiums were getting exactly what they needed, nestled in a pocket planter where just the right amount of light was available and proper watering and fertilization practices were adhered to as well. Orchids are actually quite drought tolerant and their leaves are susceptible to fungus when wet.
Over the years, I have seen five types of orchids cultivated in the Valley outdoors, including cymbidiums, whether in containers or in the ground. The most common outdoor orchids are Epidendrums, clumps of which bear clustered spherical blooms in lavender, red, pink, salmon, yellow or orange. I have seen vining Laelia orchids clamber up tree trunks, such as those of windmill palms (Trachycarpus fortunei), and I have seen Dendrobiums flourishing in rock gardens.
The easiest orchid to grow in a garden bed is Chinese ground orchid (Bletilla striata). Its pinkish-purple flowers bloom in sun to semi-shade. Chinese ground orchids also demonstrate significant cold tolerance and are tolerant of drought conditions.
All of these orchid types may be easily propagated by division of their pseudobulbs, which look like bulbs except that they can be located either above or just below the soil surface.
Upon first setting eyes on Mexican heather (Cuphea hyssopifolia), you cannot help but fall hopelessly in love. Delicate lavender-pink flowers are embedded between tiny, glistening leaves.
Although advertised for both full sun and partial shade, Mexican heather becomes old and ratty looking after only a few years of overly sunny exposure. Given sun in just the proper dose, which is no more than three or four hours of direct daily exposure, its innocent look of youth may persist for a decade.
Such persistent beauty is evident in a Mexican heather hedge that flourishes in the Valley Village condo courtyard. Here, it is occasionally pruned back but this does not keep it from returning to its compact, unblemished stature.
Of all geraniums types, Martha Washingtons probably have the most memorable blooms. Colors are brilliant, if not overpowering, yet they have a strong pastel aspect that makes you sit up and take notice. Foliage is carefully cut along the margins, adding to Martha’s overall feminine charms. Flowering generally is in late winter or early spring, yet, owing to our extended summer this year, some Marthas appear to have become seasonally confused and are blooming now, at least in the Valley Village condo courtyard.
One of the most reliable selections for containers or courtyard gardens is shrimp plant (Justicia brandegeana). It can handle most of the day’s sun but can make do on half-day sun just fine and is rather drought tolerant. Shrimp plant seems to be perpetually in bloom. ‘Red Pinecone’ is not as frequently seen as the standard burnt orange- to copper-colored shrimp plant type, but this wine to cherry-red cultivar is certain to be planted more frequently as word about it gets around.
If you are a fancier of foliage, Marguerite daisy (Argyranthemum frutescens) will find its way into your garden soon enough. Praised primarily for its dense covering of flowers in white, rose or pale yellow, its blue-green foliage is highly attractive in its own right.
A major problem with courtyard planters is that, eventually, they nearly always begin to leak. This can be a real problem if there are parking garages underneath, one floor below. To minimize water application, especially if your planters leak, and to prevent sprinkler spray from wetting walls and puddling in walkways, installation of drip irrigation in courtyard planters is advised.
Passion vine concerns
A few weeks ago you wrote about passion vines. My problem is that ours has spread all over our yard and is choking our other plants. We have had it for about 8 years. It grows nightly, has amazingly beautiful flowers and bears fruit. Still, I would like to eradicate it because of the damage. We have thought we had gotten rid of it only to find that it sneaks up on us. Any suggestions would be greatly appreciated.
— Jo Ann Koch
After donning rubber gloves, spray Round-Up or some other broad-spectrum, systemic herbicide on a sponge and rub the sponge over the leaves of your passion vine. The herbicide moves down through the stems, from leaves to roots, and kills the plant. It should be sufficient to sponge the bottom leaves of your vine to achieve the desired effect. By using a sponge, you avoid spraying any other plants.
Incidentally, this trick will probably not work with ivy (Hedera spp.), should you wish to kill it. Its waxy leaves repel not only water but also common herbicides.
Tip of the week
Australian willow (Geijera parviflora) is a drought-tolerant tree with a weeping growth habit. In Australia, sheep graze on its lower branches. In our part of the world, it is a slow growing tree with a naturally symmetrical domed canopy. Prune it sparingly and enjoy its fragrant, if not terribly showy, flowers that bloom this time of year.