This jasmine is quite a star. However, this star is technically not a jasmine. Star jasmine, Trachelospermum jasminoides, is instead related to mandevilla and oleander. For many years, it has been one of the most popular vines for home gardens as well as large scale landscapes. It works well either as a ground cover, or as a relatively docile climbing vine.
As ground cover, star jasmine gets about two feet deep. It will be lower and more refined with shearing, but will likely bloom less. It tries to climb shrubbery and trees, so will need exclusionary pruning. However, on a chain link fence, star jasmine works splendidly as a shorn faux hedge. It grows fast to more than ten feet high, but can get significantly higher.
The richly fragrant bloom is most profuse about now, and can continue sporadically until autumn. The inch wide and bright white flowers are shaped like stars, and hang in small clusters. After bloom, the distinctly glossy and dark green evergreen foliage is handsome alone. Individual leaves are a bit longer than two inches and a bit broader than one inch.
No other bloom is comparable to that of bougainvillea. It is often profuse enough to nearly obscure the foliage. The color is remarkably vibrant. Magenta is the most popular color. Purple might be the second most popular color. Other cultivars bloom in delightfully rich hues of pink, red, orange, yellow and white. Some bloom with double flowers. A few dwarf cultivars have variegated foliage.
Bougainvillea is a thorny vine that leans on its support, rather than cling to it. Like climbing roses, it must be tied or woven into trellises. Larger cultivars can mix with the branches of trees and big shrubs to eventually reach more than thirty feet high. Many cultivars stay much lower. Some grow slowly, and do not get more than three feet tall. The lush foliage is evergreen with regular watering.
However, bougainvillea does not want too much water, and actually prefers to get a a bit dry between regular irrigation. Excessive irrigation may promote vegetative growth while inhibiting bloom. Excessive fertilizer does the same. Sunny and warm exposure promotes fuller bloom. In late spring, the first and most profuse of perhaps a few bloom phases can continue for more than a month.
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.