We're looking to plant climbing vines to cover our pergola. We would like flowering vines that can withstand possible low temperatures in the 30s several times per season.
We currently have some bouganvilla but are concerned about them lasting the winter. Is there something we can do to protect them?
|Of all the flowering vines, few win more admiring looks than clematis and passion flowers. And no wonder: they bear some of nature's most alluring blooms in a range of exquisite forms and colors. Both are easy to grow in the right climates. In general, clematis prefer cooler regions, while passion flowers flourish in mild California climates.
Passion vine (Passiflora) flowers are borne on mostly vigorous vines suitable for covering fences, trellises, and walls. Hardiness varies by species and variety. In marginal climates, the vines may freeze to the ground, but plants spring back from the roots.
'Coral Glow'. Fuchsia-pink flowers are nearly everblooming in coastal areas of Southern California. Glossy, three-lobed leaves are broad. Very vigorous. Hardy to 30 [degrees]. (Similar 'Coral Seas' thrives in cooler coastal areas of Northern California and is hardy to about 25 [degrees].)
'Elizabeth'. Spectacular lavender flowers appear spring through fall. Big, 4-inch-wide leaves are a glossy yellow-green. Extremely vigorous plant. Hardy to about 25 [degrees].
'Lavender Lady'. Lavender-purple flowers have delicate violet filaments. Dark green leaves are 2 to 3 inches wide. Hardy to about 20 [degrees].
'Purple Tiger'. Spectacular purple-red flowers, with banded dark purple and blue filaments, appear all summer in Northern California, almost year-round in Southern California. Hardy to 25 [degrees].
Plant passion vines in full sun and well-drained soil amended with organic matter. The vines need little, if any, fertilizer. Water regularly to get plants established. Mature plants can get by on low to moderate water.
Train the vine up a lattice trellis or sturdy wire strung on a fence or wall. Trim off wayward branches occasionally. At the end of a plant's second year, prune out excess branches, cutting them back to the base or to another branch.
There are dozens of clematis available - here are a few of my favorites:
C. Jackmanii'. Not a true species but a cultivated variety, 'Jackmanii' bears big deep-purple blossoms from June through August. Other selections come in shades of white and red. Zones 1-9, 14-17.
C. macropetala. Lavender to powder blue flowers 4 inches wide appear from March into April. C. m. 'Markham Pink' has lavender-pink blossoms. Delicate vines. Zones 1-9, 14-17.
C. montana. Commonly called the anemone clematis, it produces masses of pink flowers resembling anemone blossoms from April into May. Two varieties are widely available: C. m. 'Rubens' and C. m. 'Tetrarose'; both have flowers with a stronger pink than the plain species. Vigorous plant. Zones 3-9, 14-17.
C. viticella. Its buds resemble candles on the vine before opening into purple or rose-purple flowers 2 to 3 inches across with gently ribbed petals that curl back. Blooms June through August. Very vigorous plant. Zones 2-9, 14-17.
Most clematis grow best in loose, cool, moist soil. There's an old saying about clematis that is essential to know: Flowers in the sun, feet in the shade. Against a south- or west-facing wall, the plant should come up from behind a shading shrub, planted well enough away that roots don't compete. The vine will need a support system to climb on: a trellis or lattice works well.
Your bougainvillea may suffer some leaf and stem damage when temperatures drop below freezing, but the roots should be fine if heavily mulched so you'll only need to prune away the damaged vines each spring. Pruning will encourage new flowering stems. Enjoy your plants!