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

Morning Glory

90807A landscape designer would have more fun describing both the modern and the good old fashioned varieties of morning glory. Their vivid colors are so resplendent. Their rich green foliage is so luxuriant. Their delicate vines are so elegant. Hey, perhaps this is not so difficult. Anyway, the popular garden varieties of morning glory are descendents of various species of the genus Ipomea.

Except for a few obscure types, and the perennial blue dawn flower, popular garden varieties of morning glory are surprisingly complaisant annual vines, which grow from seed sown at the end of winter. Without getting too invasive or weedy, they sometimes reseed where they get watered, although they might revert to a more feral state after a few generations, or after the first generation.

Some varieties of morning glory have the potential to reach single story eaves, although most stay a bit lower, and some varieties do not get much higher than a doorknob. They work well on small trellises, or even simple stakes, and are just right for picket fences. The simple two or three inch wide flowers are rich hues of blue, purple, red, pink and white, some with spots, stripes or streaks.

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.

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.

Red Trumpet Vine

60420Red trumpet vine, Distictis buccinatoria, is more green than red. The tubular orangish red flowers with yellow throats are pretty while weather is warm, but not too abundant. Slightly distressed plants tend to bloom more abundantly. Each evergreen compound leaf is a pair of leaflets with a sneaky central tendril that will grab onto anything while holdfast discs get a more permanent grip.

Vines tolerate significant shade, but will find their way to sunnier situations where they grow more aggressively. They can easily reach the roof of a two story house, and grow out of reach in trees. Their holdfast discs will damage paint, and even shingles! Overgrown plants can be cut to the ground and allowed to regenerate.

Red trumpet vine wants to be watered somewhat regularly while young. Mature plants can disperse their roots well enough to find water if they do not get it directly.

Vines Are Naturally Social Climbers

70906thumbIf more of us knew how vines compete in the wild, fewer of us would grow them in our home gardens. Understory plants that are satisfied with the sunlight that reaches them through a higher forest canopy are the most passive. Taller trees compete for sunnier exposure above. Vines are the most aggressive as they climb and overwhelm trees to get the best exposure on top of everything.

English and Algerian ivies happens to be among the more efficient of aggressive vines. While young, juvenile growth creeps along the ground searching for victims. Once it encounters something to climb, the stems develop aerial roots so that they can climb vertically. Once the climbing stems reach the top of the support, they develop shrubby adult growth that blooms and produces seed.

In home gardens, ivy is a popular and practical groundcover. However, if allowed to climb as a vine, it can root into walls and ruin paint. Even if the vines are removed, the unsightly aerial roots remain. The shrubby adult growth can overwhelm and even shade out and kill the trees or shrubbery that originally supported it. If it climbs onto a roof, it can accumulate debris and promote rot.

Creeping fig is even nastier. Its network of clinging vines grafts together as it grows, and then strangles the supportive trees as they continue to grow within the constrictive network of grafted stems. Yet, it and Boston ivy work nicely and harmlessly on concrete freeway sound-walls where their aggressive behavior is a major advantage, and their clinging aerial roots are not a problem.

Wisteria and red trumpet vine are considerably better behaved, but even they will crush lattice and anything else they wrap around. If they get into trees, they quickly grow out of reach. They may seem to be more appealing than the trees that they climb are, but can strangle and kill substantial limbs. Even without aerial roots, red trumpet vine clings with holdfast discs that damage paint.

Even though many vines are practical for home gardens, their personalities need to be considered. Star jasmine and honeysuckle can either grow as groundcover or as climbing vines. They can get big, but are not often destructive. Potato vine works nicely on fences, but gets aggressive in trees. Carolina jessamine, lilac vine and mandevilla are some of the more complaisant of vines.

Horridculture – Ivy League

P90306English ivy, Hedera helix, is probably the nastiest and most aggressively invasive exotic species that I work with. It climbs high into redwood trees and overwhelms understory plants (that live below the trees). It invades many of the landscapes, and worst of all, it climbs building where it ruins paint and causes rot. It grows faster than we can keep up with it.

English ivy is actually a nice ground cover plant for refined landscapes. I grew it at my home in town. Contrary to popular belief, it does not root into and parasitize the trees that it climbs. Actually, it rarely overwhelms and shades out large trees. It prefers to keep them alive for support, from which it disperses its seed. However, it does promote decay in the trunks that it climbs, particularly where it retains moisture at ground level. Native trees are not accustomed to that.

We try to remove as much English ivy at work as possible, which includes removing it from trees and buildings. So far, with a few exceptions of small bits of ivy that broke off high in the trees that it climbed, I have been able to remove all ivy from the trees and walls that I have worked on.

Others were not so fortunate. When quick and efficient removal of ivy from the bases of as many mature trees as possible is the priority, ivy is more often severed down low, and left to die on the trunks of the infested trees. It looks shabby to say the least, and takes many years to deteriorate and fall away. In the picture above, dead ivy that was severed within the past few years is already being replaced by new ivy, which will also need to be severed.

The same technique happens with ivy on buildings. It gets cut at the foundations, but left on the walls to shrivel and turn brown. The dead ivy in the picture below was reaching upstairs eaves when it was severed, and remains there a few years later.

What annoys me so much about this technique is that it does not take much extra effort or time to tug quite most of the lower ivy from trees and walls. For most situations, all ivy can be dislodged, although tiny aerial roots remain. It is much easier to dislodge while fresh than after it is dried and crispy.P90306+