Since it rarely gets cold enough here to freeze the foliage and stems, clock vine, Thunbergia gregorii, provides very orange flowers throughout the year, and will bloom more profusely in summer. It is very similar to the more traditional black-eyed Susan vine, but the flowers lack the prominent black throats. Relative to most vines, orange clock vines is rather docile. The wiry vines are happy to climb to the height of first floor eaves, but do not go much farther. Without support, the vines grow as small scale ground cover.
New plants prefer full sun exposure, even if they later choose to spread into partial shade as they grow. Shade inhibits bloom. Once established, orange clock vine does not need much water, and can actually survive in abandoned landscapes. Overgrown or neglected vines can get weedy in spots, especially if not regularly watered. Fortunately, they are easily renovated by severe pruning at the end of winter. Even if pruned almost to the ground, vigorous vines regenerate very efficiently.
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.
A 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.
Whether it is grown intentionally, or considered to be a common roadside weed, there is no denying that perennial pea, Lathyrus latifolius, knows how to brighten some of the wilder parts of the garden with brilliant purplish pink bloom. Some garden varieties bloom either pale pink or white, just like a few random feral plants do. Bloom resembles that of sweet pea, but without fragrance.
By their second year, the potentially six foot long vines might be a bit too rampant for more refined situations. They happen to work nicely to climb over wood piles and otherwise unsightly chain link fences though, even if only temporarily until they die back to their fat subterranean taproots by the end of summer. They will be gone before the firewood they conceal becomes useful again.
New bluish green growth regenerates vigorously at the end of winter, but does not bloom until early summer. The compound leaves are comprised of only a single pair of narrowly oblong leaflets with a branched tendril in between. Each leaflet is about two inches long and less than half as wide. Stems and petioles are winged. Once established, perennial pea can be difficult to eradicate.
Red 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.
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.
Even within its native range, blue dawn flower, Ipomoea indica, can be a problem. There are not many other plants in some coastal regions of Peru that can avoid getting overwhelmed by the aggressive wiry vines. These vines grow roots where they touch soil, so can spread indefinitely over the ground. Vines that succumb to frost over winter regenerate as if nothing ever happened.
Three inch wide flowers are rich purplish blue when they open at dawn. They then fade through the day, only to be replaced by fresh new flowers the following morning. Bloom continues from spring until autumn, and can get profuse at times. The lush rich green leaves are cordate (heart-shaped) or lobed (with only three lobes). Too much fertilizer promotes growth but inhibits bloom.
Blue dawn flower’s main weakness is a dependency on water. If it gets too dry briefly in summer, it can die back like it does with frost, and then recover once it gets water, but it will not survive for very long if it stays dry. As aggressive as it is, it should not spread very far from landscaped areas or riparian areas where summers are too warm and dry for it.
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.
There 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.