Compared to the common passion flower, the three inch wide red passion flower, Passiflora manicata, is more colorful with cherry red flowers, but does not so prominently display the weirdly distended floral parts that passion flowers are known for. Bloom is not as profuse either, particularly among vigorous vines.
However, red passion flower vine has the advantages of somewhat more resilient and greener foliage, and sturdier vines that can climb almost to thirty feet high. It grows so vigorously that it can be surprisingly overwhelming, even if pruned severely or cut to the ground at the end of each winter. It is not so rampant in light shade.
Copies (new vines) are easy to propagate by layering, which involves merely burying a section of vine while still attached to the parent vine until it develops enough roots to be separated. The buried section should be at least a few inches long. At least a few inches of the tip of the vine should extend beyond the buried section.
The fruit of red passion flower vine is considered to be toxic, but often gets eaten anyway. Fortunately, fruit rarely develops.
Boston ivy and creeping fig are good aggressive vines for freeway overpasses and sound-walls. They are resilient to harsh exposures and pollution, and help to muffle the sound of traffic. Boston ivy provides remarkable foliar color in autumn before defoliating in winter. Creeping fig provides thick evergreen foliage that overwhelms any graffiti that it can reach.
However, their aggressive behavior that is such an advantage on freeways is precisely why they are not so practical for home gardens. Boston ivy gets around so efficiently because it grabs onto surfaces with ‘holdfast disks’ (modified tendrils) that damage paint, stucco, wood and just about anything that is not built like a freeway. Creeping fig is at least as destructive with clinging aerial roots, as well as constrictive stems that can crush smaller plants, fences and anything else that it might grab hold of.
Most vines are aggressive in nature. They exploit trees for support, and then compete with them for space. Some are complaisant enough to mingle relatively peacefully with the trees that support them. Less honorable vines have no problem overwhelming the canopies of their supportive trees. Creeping fig and other related figs are known as ‘strangler figs’ because their constrictive roots and stems crush and kill the same trees that help them get above the forest canopy.
Such behavior needs to be considered when selecting vines for home gardens. Bulky and potentially constrictive wisteria vines that would tear lattice apart can be quite appealing on sturdy arbors or trellises. Lattice could instead be adorned with docile Carolina jessamine, lilac vine, mandevilla or even regularly pruned passion vine. Star jasmine and the various trumpet vines work nicely to obscure chain link fences. With regular selective pruning, pink jasmine, honeysuckle and potato vine work well on rail fences.
Climbing roses and bougainvillea do not climb on their own, but can be trained almost like vines. Some varieties stay small enough for low fences and trellises. Larger types are proportionate to larger fences and arbors.
The scrub palm incident should have reminded me that there is such a thing as too much of good thing. By the way, I do intend to grow every single seedling that germinates and somehow find homes for them all. I suspect that almost all will live in my own garden, but at least I know they will live in a good home. I have grown surpluses before, and I actually plan to do it again.
For examples, that big herd of cedar seedlings that was partly reassigned into landscapes is just too numerous for all seedlings to be accommodated. Most of what remains will get canned to be installed into landscapes later. Since we planted about as many as we possibly can here, most will likely go to Los Angeles, and installed onto embankments of the Santa Monica Freeway.
That is too many cedars; but I just can not bear to discard them as I should. Nor can I leave them to grow into a crowded and likely rat infested grove. They should be happy in Los Angeles.
Anyway, I was asked to grow a few copies of Boston ivy for a pair of concrete columns that support a pedestrian bridge. Two specimens were already planted on two other concrete columns of the same pedestrian bridge, from which English ivy had been removed. Two other specimens grow on a concrete retaining wall from which Algerian ivy gets removed ahead of its advance.
I should have just plugged a few cuttings into a can, and then separated them and plugged them directly into the landscape as they rooted. Instead, I plugged cuttings into a flat. Well, I could not just plug a few, and leave the rest of the flat empty. I filled an entire flat with a hundred cuttings. I expected a high mortality rate, but alas, almost all of the cuttings are doing quite well.
Now we are finding all sorts of concrete retaining walls and other infrastructure where we can plant Boston ivy. We are also realizing that there is a difference between ‘can’ and ‘should’. As I was dumping greenwaste, I noticed how austere this big water tank looks. Boston ivy would really appreciate all that surface area! There is enough to plant all the way around the perimeter!
Then, I thought of all the reasons why clinging vines are not allowed onto water tanks. They deteriorate the paint, which allows the tanks to rust. They allow rodents to climb up to the top of the tank, which is really not a good place for rodents. They need maintenance, which is not justifiable for landscape features that serve no practical purpose. They need (ironically) watering.
If the tank were in a more prominent location where it should be obscured, it would be best to plant dense evergreen trees, such as cypress trees, around it. Such trees would be planted at a distance, to maintain reasonable clearance. Really though, the tank is in a secluded place, where not many of us see it. It needs no landscaping, so will remain as austere as it has always been.
But, what about the cyclone fence around the water tank? All those surplus grape vines could most certainly make good use of it as a trellis! Okay, I get it. It would take too much work, and there is too much potential from problems . . . rodents, maintenance, watering, damage to the fence, and half of all the grapes would be locked inside where only a few of us could get to them.
This 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.
‘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.
Urban 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.
Most 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.
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.
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.
Pink, 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.
Like 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.