Why Autumn Is Also Fall

50923thumbNow that leaves are falling, they need to be raked. Large leaves, like those of sycamore and fruitless mulberry, can shade out lawn, shallow ground cover or dense shrubbery. If shade is not a problem right away, mildew can be after only a bit of rain. If abundant enough, finely textured silk tree or jacaranda foliage that typically sifts harmlessly through shrubbery and most ground cover, can accumulate and damage lawn, dichondra and the densest of ground cover. Walnut foliage has an herbicidal effect on sensitive annuals and some perennials.

Foliage is only beginning to fall. Cooling weather causes deciduous trees to shed more. Rain and wind bring the foliage down even faster. Even evergreen trees that naturally shed throughout the year will likely shed more through the upcoming wintry weather. Some trees start to defoliate early in autumn. Some hold their foliage until frost. Some trees that seem to be evergreen hold their foliage through winter, and then only drop their older foliage as it gets replaced by new foliage as winter ends.

Pavement and decks should be raked of leaves, not only to avoid staining, but also because rotting leaves can become dangerously slippery. Curbside gutters are too visible to get neglected for too long. However, heavy rain can quickly deliver to the cleanest of gutters a mess of fallen leaves as well as any other debris and litter that happens to be up the road. Strong wind can be filtered through hedges, leaving drifts of blowing leaves.

Leaves should also be cleared from roof gutters and downspouts, and may need to be cleared away again later in the season. More debris may need to be removed from awkward spots where it might accumulate, such as behind chimneys. Flat roofs may need to be raked.

There are a few exceptions to the need to rake fallen leaves. Where they get absorbed into coarse ground cover like Algerian ivy, falling leaves are generally not a problem. Pine needles and cypress foliage can be left if it happens to be useful for the natural suppression of weeds. Mature coast live oaks and valley oaks that are accustomed to a layer of their own fallen leaves over the surface of the soil actually want it to stay. For them, the foliar debris is a mulch that adds organic matter, insulates the soil, and retains moisture.

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Garden Verbena

60629It is fair to say that garden verbena, Verbena X hybrida, is a reliable warm season annual. It gets planted in spring to spread out and bloom through summer with bright pink, red, purple or almost blue, or softer pastel pink or pale white. It is commonly replaced with cool season annuals by late autumn. However, garden verbena is actually a short term perennial that can survive winter to bloom for a few years.

Perhaps individual plants do not last long enough to be practical as permanent ground cover. Yet, if mulched just so, the thin branches can root where they touch the ground, and then grow into new plants to replace the original plants before they die out. Stems do not spread or cascade much more than a foot from where they are rooted. Nor do they stand more than six inches deep.

Star Jasmine

90619There is some debate about the origin of the common name of Confederate jasmine. Some attribute it to its popularity in the former Confederate States of America. Others believe it originated in the Malay Confederacy, much closer to its native range. That is irrelevant here, where we know this popular vine with very fragrant flowers simply as star jasmine, Trachelospermum jasminoides.

One might think that it is too common, but there are reasons for that. The dark green foliage is so delightfully glossy all year. As appealing as it is alone, it is even better as a contrasting backdrop for the small but strikingly white star shaped flowers that bloom in profusion about now, and continue to bloom sporadically for much of the rest of the year. The lavish fragrance is totally awesome!

The twining vines climb luxuriantly to about the height of first floor eaves. They can climb much higher, but higher growth takes a while to get as billowy as lower growth. However, it is more often grown as a shrubby ground cover, only about two feet deep. The simple leaves are two to three inches long, and one to one and a half inches wide. The clustered flowers are about an inch wide.

Vines For Better Or Worse

90619thumbVines in the wild are downright exploitative. They do not support their own weight, so instead climb or sprawl over shrubbery and trees. Some are satisfied staying down below the canopy of the hosts who support them, as if aware that a healthy host will support them for a good long time. Many vines climb aggressively to the top and overwhelm their hosts, even if it eventually kills them.

There is nothing civil about the technique of the strangler figs, which incidentally includes two popular houseplants, fiddle-leaf fig (Ficus lyrata) and creeping fig (Ficus pumila). They wrap their hosts in networks of stems and roots that strangle the hosts as both the hosts and the clinging vines grow and expand. As the hosts die and rot, the vines develops into self supporting tree trunks.

That is how fiddle-leaf fig, as it is known as a houseplant, grows as a free standing tree rather than as a creeping vine. It is grown from cuttings from the self supporting adult growth rather than the creeping juvenile growth. Conversely, creeping fig is grown from juvenile vines, which find a support to cling to, and ultimately develop shrubby adult growth when they get to the top of the support.

English and Algerian ivies are not quite as aggressive, since they do not intend to kill their hosts. They are not often intentionally grown as vines, and are almost never planted anymore, but their juvenile growth still works as ground cover in many mature landscapes. One of the main problems with ivy is that it is constantly trying to climb walls and trees so that it can bloom and toss seed.

That is not such a problem on concrete walls, but ruins wooden and painted surfaces, and makes a mess of trees. Boston ivy (which is not really an ivy) lacks a juvenile ‘ground cover’ phase, but if kept off of painted and wooden surfaces, happens to work better on concrete infrastructures. It is important to know how a particular vine will behave before selecting it for a particular application.

Carolina jessamine, mandevilla, lilac vine and star jasmine are a few complaisant vines.

Coast Rosemary

51223Just like real rosemary, the coast rosemary can either be a low ground cover or a dense shrub. Lower cultivars can get nearly five feet wide without getting much more than a foot high. Shrubby types can get nearly six feet tall without getting much wider. Shrubby types are more popular than ground cover types, and are often pruned so that they do not get too broad.

The tiny leaves of coast rosemary are silvery or grayish green, and can be variegated. Small white or very pale lavender flowers bloom sporadically throughout the year, and can be profuse in spring. Established plants do not need much water, but are probably happiest if watered somewhat regularly through summer. Shade subdues silvery foliar color and inhibits bloom.

Shrubby coast rosemary makes a delightful low hedge. It can be shorn like any other formal hedge, but is best where it has space to develop naturally. If space is limited, but not ‘too’ limited, a coast rosemary hedge can be aggressively shorn once annually at the end of winter, and then allowed to grow wild for the rest of the year.

Carpet Rose

51028They compare to more traditional roses like instant coffee compares to real coffee. They are too easy and cheesy. However, even instant coffee can be rather good as long it is not expected to taste like the real thing. Likewise, carpet roses do not produce big and fancy flowers on long stems for cutting, but they have other attributes that are advantageous in the landscape.

The small but ridiculously abundant roses that started blooming late last spring are only now finishing. Bloom can be white, pink, red, coral, scarlet, gold (orangish yellow), yellow or white. The rich green foliage is remarkably resistant to disease, and lasts until frost. The arching stems can spread a few feet without getting much more than three feet tall. Most cultivars stay shorter. Some get quite wide.

Like other roses, carpet roses will need to be pruned back severely while dormant in late winter. Yet, they do not need to be pruned nearly as carefully. Because they grow as thickets of canes, they do not need to be thinned to only a few canes when pruned. Even if old canes do not get pruned out, they will get overwhelmed and replaced by newer canes naturally.

Creeping Myoporum

80912The familiar sandalwood, Myoporum laetum, that is such a resilient small tree or big shrub in windy coastal climates, might make the wrong impression for the less familiar creeping myoporum, Myoporum parvifolium. Creeping myporum does not get much more than a foot high unless it climbs over stones or other obstacles, and it might stay less than six inches deep in exposed spots.

The evergreen foliage is dense enough to prevent most weeds from getting through. The tiny and narrow leaves are only about half an inch or an inch long, perhaps a bit longer. Clustered white starry flowers that begin to bloom late in spring continue to bloom through summer. Although tiny, and neither profuse nor remarkably showy, they are a nice accent to the rich green of the foliage.

Creeping myporum prefers full sun and occasional watering. It rots easily if watered too much. Its other weakness is that it does not tolerate traffic well. Creeping myoporum is a low growing shrub with woody stems that can break if trampled on. Individual plants can get ten feet wide if they get the chance. They are typically planted much closer together so that they cover the ground faster.

Groundcover Is Carpeting For Landscapes

80912thumbIf shade trees are the ceilings, and hedges and shrubbery are the walls, then turf and other groundcover plants are the floors of some of our outdoor living spaces. Except for turf grasses, most groundcovers are not as useful as hardscapes like pavement and decking, but they perform other functions in areas that do not get such use. Groundcovers inhibit weeds, erosion, dust and mud.

Turf grasses used for lawn are of course the most popular groundcovers, and are a separate topic from other groundcover plants that grow over unused or lightly used ground. Because they need not tolerate traffic, these other groundcover plants need not be as resilient, or as flat as turf grasses are. They can be perennials, vines or low sprawling shrubbery. Most, but not all are evergreen.

Groundcover plants work something like mulch, although most want to be watered. They inhibit weed growth by occupying the space that weeds want. Many hold soil together with their roots. They may seem like they would compete with other plants, but groundcover plants insulate the soil, which makes it more comfortable for other plants. Many retain more moisture than they utilize.

Gazanias and iceplants are two of the most popular perennial groundcovers. They tend to replace their own growth regularly as old stems decompose below new growth that spreads over the top. They therefore do not get very deep. Some gazanias eventually develop bald spots. When they get trimmed around the edges, the scraps can be plugged back into bald spots as cuttings.

Cultivars of myoporum, cotoneaster, ceanothus, rosemary, juniper and other low and sprawling shrubbery that make good groundcover must not be confused with cultivars that grow as upright shrubbery or even trees. There is a big difference between creeping myoporum that stays less than a foot deep, and shrubby myoporum that can get almost thirty feet tall! Also, vines used as groundcover, like ivy and honeysuckle, should be maintained as such, and not allowed to climb trees, shrubbery and other landscape features, like vines naturally want to do.

Periwinkle

70503Like so many of the easiest to grow plants, periwinkle, Vinca major, is too easy to grow. It has become an invasive exotic (nonnative) weed in many moist riparian environments. It can get rather weedy in home gardens as well. This can be an advantage if it happens to fill in for bald spots in areas of other ground cover. It is a disadvantage if it overwhelms or competes with other plants.

It is hard to believe that such a seemingly innocent plant with sporadic but delightful light blue flowers amongst rich green foliage has such unpleasant potential. The radial flowers are about an inch or maybe two wide, and bloom almost all year except for winter. The simple evergreen leaves are likewise an inch or two long. The wiry stems stand a foot or two high before flopping over.

Once stems lay down, they develop roots where they touch the ground, and form new plants that repeat the process of producing upright stems that flop over. Without confinement, there is no limit to the trouble they can get into. Fortunately, it is not a fast process. Cultivars with white or purple flowers, or variegated foliage are more complaisant. Periwinkle is neater if mown as winter ends.

Get The Lowdown On Groundcover

1Lawns composed of turf grasses are the most functional, but also the most demanding forms of groundcover. That is old news. There are so many other less demanding low growing plants that that can cover the ground in areas that are not used like lawns are. Sometimes they work nicely just to control weeds. Sometimes they help to control erosion on otherwise unlandscaped hillsides.

Like all other plants in the garden, groundcover plants must be appealing. There is no point in growing plants that look no better than the bare soil they are intended to obscure, or the weeds they are intended to control. Some provide good foliage. Some bloom nicely. Many do both. Although not as resilient to wear as turf grasses, some groundcover plants tolerate some degree of traffic.

There are of course all sorts of groundcover. Only a few want as much water as lawns need. Some need no watering at all once established. Some are low growing shrubbery like sprawling forms of ceanothus, coyote brush, cotoneaster, coprosma and juniper. Others are vines like honeysuckle and ivy. Some of the best are creeping low perennials like iceplant, gazania and African daisy.

Low growing shrubberies may not be practical for confined spaces. When they run out of room to grow laterally, they tend to pile up on themselves, and some types can eventually get quite deep. Some types look silly if pruned around the edges for containment. Vines however need to be pruned around the edges, as well as out of trees and shrubbery. Some vines eventually get deep too.

Sprawling perennial groundcovers are the lowest and tidiest of groundcovers. They might not be as practical as shrubbery or vines for large areas, but are more often the better options for tight spaces. They do not mind getting pruned around the edges, and generally do not need any other pruning, although some look better if mown annually. Periwinkle and Saint John’s wort can get deep enough to get sloppy. Many other perennial groundcovers stay low enough to barely get disheveled by light trampling.2