Chilean Jasmine

90814This is not just another mandevilla. Well, maybe it is. Mandevilla laxa is special though. It is known as Chilean jasmine because, unlike other mandevillas, it is so delightfully fragrant, particularly on warm summer evenings. Some say the fragrance is similar to that of gardenia, but not as strong. Others say it has a bit of vanilla mixed in. Sporadic bloom continues through most of summer.

The two inch long pure white flowers flare out to be a bit wider than long, and are a bit more relaxed than the neatly tailored flowers of other mandevillas. They bloom sequentially in small groups, with new flowers replacing the old for quite a while. The glossy rich green leaves can get almost twice as long at the flowers. Foliage last better on the coast, but is mostly deciduous elsewhere.

Chilean jasmine grows fast in spring, especially if pruned well after winter, but is surprisingly tame. It can grow past downstairs eaves, but should not reach upstairs eaves. It is satisfied with a light duty trellis. If carefully pruned out and removed each winter, it is one of the few vines that is complaisant enough for lattice. Light frost can kill stems to the ground, but they usually recover in spring.

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Mandevilla

60803‘Alice Dupont’ mandevilla that was so popular through the 1980’s was already a cool vigorous but not too overwhelming vine, with big clear pink radial flowers. It grows rather vigorously to upstairs eaves, and tends to get bunched where it reaches the top of its support. Modern cultivars with red, white or bright pink flowers are more compact and tame, and can stay below downstairs eaves.

The wiry twining stems neither root into their support like ivy does, not get bulky enough to constrict and crush their support like wisteria does. However, old vines might get thick enough to split lattice apart. New plants are greener in partial shade, although they will probably climb to where they get full sun exposure. The glossy evergreen foliage is surprisingly sensitive to even mild frost.

Mandevilla is tropical, so enjoys warmth, but not aridity (minimal humidity). Overly exposed foliage can get scorched by hot weather. Sporadic bloom continues from spring through autumn, with more prolific bloom phases in response to warm weather. Unfortunately, mealybug, aphid, scale and whitefly enjoy warm weather too. While pruning, the caustic white sap can be a toxic nuisance.

Vines Do Not Replace Hedges

90619thumbUrban homes are innately close to other urban homes. Newer homes are even closer to each other than older homes are, and are more imposing. Establishing or maintaining privacy can be a challenge, especially for high windows in narrow spaces. Even though home builders prefer to place windows strategically, some windows invariably face into neighboring windows or gardens.

Trellised vines are a popular but rarely effective remedy to this dilemma. The narrow spaces between houses and below the eaves can be dark enough to inhibit growth. Consequently, vines are typically sparse or bunched on top of their trellises. Their most vigorous growth is often awkwardly long shoots trying to find a way out of the shade. Vines are not exactly easy to work with anyway.

There are of course exceptions. With regular maintenance, some finely textured vines that are reasonably tolerant of shade can be effective for downstairs windows. (Upstairs windows are out of reach.) If shorn very regularly, English ivy on lattice works almost like a hedge. (Ivy does not fill in on more open trellises.) Trellised star jasmine is even better, but needs more depth (front to back).

Yet, with few exceptions, big evergreen shrubs or small evergreen trees that tolerate shade are more practical. They support their own weight, so only need to be pruned for confinement and clearance from the houses that they provide privacy for. Some shrubs and trees should be pruned to stay at the desired height, so that superfluous upper growth does not shade out lower growth.

The various podocarpus are some of the better small trees for narrow spaces between houses because they are are somewhat tolerant to shade, and are so easily pruned into shape. Some of the taller and more upright pittosporums work nicely in sunnier spots. Arborvitae tolerates more shade, and naturally stays narrower. Since some of these better options might grow slowly, they can be planted with faster growing shrubbery that can be pruned back, and eventually removed as the preferred plants mature.90619

Docile Annual And Perennial Vines

90710Most of the familiar vines really are exploitative bullies. They shade the same trees and shrubs that they climb for support. Some will even strangle and kill those who make it possible to get where they want to be. If they do not find trees or shrubs to victimize, they are likely to climb walls and ruin the paint, stucco or siding. Their aggressive nature can be a problem in landscape situations.

Fortunately, there are several vines that are not so aggressive or destructive, such as mandevilla, lilac vine, star jasmine and Carolina jessamine. Other vines that are even more complaisant are light duty perennials and annuals that might grow like weeds while the weather is warm, but then do not have enough time to grow too big or do much damage before they die back through winter.

If flashy color is not important, vining vegetable plants such as pole beans, cucumbers and peas, can cover fences very nicely. On flat fence surfaces, such vines will climb string strung in a vertical zigzag pattern between a horizontal row of protruding nails at the top, and another similar row at the bottom. Unsightly cyclone fences are even better, but will need be harvested from both sides.

Although it is too late to sow beans and cucumbers, a new phase of peas can be sown in mid summer for production in autumn. Fragrant and subtly colorful sweet peas, which are grown for their flowers rather than as vegetable plants, take considerably more effort here. They get started in autumn for the following spring. Trailing nasturtium can get sown at any time, for summer or winter.

As the name implies, perennial pea is a perennial that can get almost rampant, but dies back by autumn.

Passion fruit vine can either be a perennial that dies back to the ground in winter, only to regenerate the following spring, or a somewhat woody vine with wiry stems that survive for several years. Those that retain their vines through winter can get cumbersomely big, or can alternatively be cut back severely late in winter, to behave almost like more docile types that die back for the winter.

Horridculture – Well Done Stakes Are Rare

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Stakes are temporary. That is what so called maintenance ‘gardeners’ do not seem to understand. Stakes should not stay any longer than necessary, so need to be removed sooner than later, depending on their function. Stakes that are left too long can interfere with the healthy development of the trees and vines that they were intended to help.
Nursery stakes are used either to straighten the trunks of developing trees, or to support climbing vines. They must be removed when the trees or vines that they worked for get installed into the landscape, or as soon after installation as possible. Some flimsy trees may need their stakes for more than their first year.
The problem with leaving trees bound to their nursery stakes for too long is that they rely on the stakes for support as they grow, so do not put much effort into supporting their own weight.
The picture above shows a coast live oak that was staked properly with landscape stakes to the side, but while still bound to the original nursery stake. Because the tree was bound for too long as it grew, it may be too flimsy to support itself without bending when the binding nursery stakes eventually gets removed. For this particular tree, the bindings may need to be removed in phases so that the tree can learn to support itself before the last binding is cut loose.
The problem with leaving vines bound to their nursery stakes is that they remain bundled in the middle while new growth spreads out more naturally. Vines should instead be unbound and spread out onto their support, even if they need to be bound to the new support like they were bound to their nursery stake. Only a few vines that will get cut to the ground annually or after their first growing season, such as Boston ivy and creeping fig, can remain bound through their first year, only because the whole mess will be pruned to the ground, and replaced with new growth later.
The picture below shows a pink jasmine vine that is still bound to its stake, right in front of a disproportionately small trellis. The bundled mess of stems in the middle is partially obscured only because the tangled upper growth is so overgrown. There are so many problems with this unfortunate potted pink jasmine that it will be a topic for next week.P81128+

Landscape stakes are very different from nursery stakes. They are not needed to straighten trunks of trees, but are merely used for a little bit of support while new trees disperse their roots. When trees have adequately dispersed their roots and are stable enough to stand up to a bit of wind on their own, landscape stakes must be removed. They are not as likely to interfere with the development of structural integrity like nursery stakes do, but can interfere with root dispersion and development of adequate stability if trees become reliant on them for support.
The flowering cherry tree in the picture below obviously does not need the support of the unsightly landscape stakes that remain partly strapped to the trunk. The stakes did not compromise stability only because the tree is so naturally stout. The stakes really are unsightly though. So is the overgrown Boston ivy on the trunk and up into the canopy, . . . and the mutilated stubs and stems that were ‘pruned’ by the maintenance ‘gardeners’. Seriously; what kind of ‘gardener’ does this sort of atrocious work?! Well, those topics can be addressed at another time.P81128

Mandevilla

70621Pink, red or white are the only choices. There happens to be a darker shade of red. Yellow throats are more conspicuous in white flowers. Otherwise, there is not much variation of color amongst the various mandevillas. The flowers are very similar in both color and form to those of related oleander, but are larger. Some are as wide as three inches. Small flowers can have pointed petals.

Mandevilla vines are surprisingly vigorous and sneaky. The lower portion of a mature plant may seem to be rather tame while it extends aggressively twining vines into trees above. Vines on small trellises can get congested on top. Pruning upper growth helps to even out growth and bloom. Exposed vines are likely to get killed back by frost in winter, but should regenerate efficiently.

The evergreen foliage is quite glossy. Some varieties have interestingly rippled leaves. Partial shade is best for rich green foliar color. Full sun can scorch leaves. Dipladenias are very similar to mandevillas, but are shrubbier and more compact, with smaller flowers and leaves. They are probably a better option for large pots. Sap of both mandevillas and dipladenias is caustic and toxic.

Anemone Clematis

70531Like Ginger and MaryAnn, choosing between the flashier hybrids of clematis and the anemone clematis, Clematis montana, might not be so easy. The fancier hybrids have the bigger, bolder and richly colored flowers that the genus is known for. Anemone clematis has smaller and more subdued flowers in soft pastel hues, but is more prolific, more vigorous, and blooms for nearly a month.

The simple spring flowers look something like those of dogwood, except that they are on wiry deciduous vines that are already outfitted with new foliage. Most are soft white with only four petals and prominent yellow anthers. Some are blushed, pale pink, rose pink or pinkish mauve; and some have more petals or fluffier ‘double’ flowers. The largest flowers are a bit wider than two inches.

The vines are more vigorous than those of clematis hybrids, but are not as aggressive as most other vines or winter clematis. With pruning, they can behave on small gate arbors, although shorter trellises would probably be too confining. If vines escape confinement, they can eventually climb more than thirty feet. The distinctively lobed trifoliate leaves are olive drab, and handsomely rustic.

Grapes And Vines Of Wrath

70531thumbAnyone can plant a grapevine. With a bit of work, almost anyone can make a grapevine grow. Most who put forth the effort can figure out how to prune and cultivate a grapevine. Yet, grapevines so often get very out of control. They easily escape confinement, overwhelm nearby plants, climb into trees and overburden their trellises or arbors. It is easy to forget how aggressive they can be.

The primary problem with aggressive vines is that they require pruning for confinement. The most aggressive vines need the most aggressive pruning. Grapevines can actually be quite docile if pruned properly. Chinese wisteria and red trumpet vine need even more aggressive pruning, and will never be completely tamed. It is important to know the personality of each vine in the garden.

The secondary problem with aggressive vines is they are expected to conform to unrealistic confinement. Small trellises that are lower than about eight feet, including common gate arbors, spires and obelisks, are really only big enough to accommodate docile small vines like clematis (hybrid), American wisteria, well pruned mandevilla and vining annuals like morning glory and pole bean.

Chinese wisteria, large types of bougainvillea and other big and heavy vines need big and stout trellises or arbors. Lattice will not do. Chinese wisteria becomes entangled with lattice, and then crushes it as the vines expand. Bougainvillea does the same to a lesser extent, but then pulls the lattice apart as the intertwined vines sag from the increasing weight of foliage and growing vines.

Clinging vines like creeping fig and Boston ivy present another problem. They are not interested in trellises or arbors. They do not grab onto support by twining stems or tendrils. They instead cling directly to surfaces with specialized aerial roots that damage paint, stucco or even bare wood fences. Clinging vines should therefore only be allowed to climb surfaces that they will not ruin, such as concrete walls. They are better vines for freeway soundwalls than for home gardens.

Clematis

70524There are so many different specie involved with the extensive breeding of the modern cultivars of clematis that they are not even assigned full Latin names. They are simply known as ‘clematis’ (without a specie name), with a respective cultivar name. Clematis X jackmanii is the oldest known hybrid, so the name is often applied to other hybrids, whether or not they are actually related.

The big broad flowers are abundant and spectacular this time of year, but unfortunately do not last long. Bloom finishes before the weather gets much warmer, leaving unimpressively rustic foliage on wiry vines. The vines might reach ground floor eaves, and are just the right size for small gate arbors. If necessary, old plants can be lightly groomed of twiggy growth while bare through winter.

Flowers are rich shades of blue, purple, red, pink or white. Many are bi-colored, and some have ruffled centers. During full boom, there may be more flowers than foliage visible. Foliage is a dark shade of olive green, with a dull matte finish, which is actually a perfect background for the rich color of the bloom. Roots like rich, moist and cool soil, while the vines climb into sunnier situations.