My garden can accommodate one or two. I couldn't have guessed that all of them would grow into new vines.

With few exceptions, vines are innately aggressive. In the wild, most species of vines want to get to the top of a forest canopy by climbing trunks and limbs of trees. They then spread out over the canopy, overwhelming the same trees that had been so supportive. Some vines are so aggressive and profuse that their shade can be fatal to the trees below. A few, such as the strangler fig, will actually constrict and kill its supporters. It is amazing that so many species of vine are adaptable to home gardens.

The various species of vines get to the top by different means and with different degrees of aggressiveness. Some use tendrils or "holdfasts," which are both types of modified leaves, to grip their support. Some climb by twining stems that wrap around support. Some even grip with aerial roots. A few do not actively climb at all, but lean onto and over their support. Natural characteristics of each species are appropriate for particular functions in the garden, but may be very inappropriate for others.

Boston ivy that uses holdfasts to climb limestone cliffs, and strangler fig (creeping fig) that uses aerial roots to climb wide tree trunks, proficiently climb flat surfaces. Both can aggressively climb walls and damage paint, siding and shingles. However, they are useful on unpainted reinforced concrete or cinderblock structures. Grape is related to Boston ivy, but uses tendrils to more complaisantly climb a trellis or arbor.

Wisteria, pink jasmine and honeysuckle climb by twining stems. Wisteria is so aggressive and becomes so heavy that it needs a very sturdy trellis or arbor and requires regular pruning. Pink jasmine and honeysuckle will probably be satisfied with a lighter trellis or a chain link fence.

Bougainvillea can be very vigorous, but does not actively climb. It instead sprawls over support. It can be supported by a trellis or a wall, but will expect to be tied into place. "Climbing" roses, whether small and delicate or large and robust, behave similarly.

Many species behave differently when they are seeking support, climbing support, or have reached the top of their support. The juvenile form of ivy that most of us know as a ground cover searches for support. The mediary form is what climbs trees that have been discovered by the juvenile growth. The shrubby adult growth that appears over the supportive trees is what blooms, fruits, and disperses seed. All three are specialized parts of the same vine.

Flower of the Week:
Beard tongue

Beard tongue is such an odd name for Penstemon gloxinioides. "Border penstemon," "garden penstemon" or simply "penstemon" are three other more common names. The many varieties of this species are actually selections or hybrids of another species (Penstemon hartwegii). They are perennial, but only last about four years. Fortunately, replacement plants are easily grown from cuttings or lower stems that root where they lay on the surface of the soil as older plants deteriorate. Shrubby mature plants are rounded and about three feet tall.

Each vertical floral spike suspends several small tubular flowers that are popular among hummingbirds. Floral color range includes white, pink, red and purple. Primary bloom appears in late spring or early summer. Large plants may also bloom lightly in autumn if sheared after first bloom.

Penstemon enjoys full sun exposure and good drainage. Established plants do not require much water and are actually very susceptible to root rot if irrigated too frequently. Penstemon is generally available in No. 1 cans (one gallon). Larger plants are rarely available in No. 5 cans (five gallon), but these are more likely to have difficulty becoming established in the garden.

Horticulturist Tony Tomeo can be contacted at 408.358.2574 or at LGHORTICULTURE@aol.com.