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The word vine is a broad descriptive category for plants that undergo the process of vining, or elongation
of the stem. This elongation is an adaptation by the plant to its environment. These plants have evolved to
climb for space in which to grow and seek out light. However, this alone does not define what a vine is
as these same characteristics would also apply to groundcovers. The distinguishing line between a
groundcover and a vine is not a clear one and many plants could be considered as both. What we refer
to here as "vines" are large vigorous plants that climb vertically but lack the ability to sustain their height without support. In the
words of Edwin A Menninger in Flowering Vines of the World : Vines have "the impulsion to elongate
without proportional lateral growth" More Quotes from Menninger. To add further confusion to this
discussion, it should be noted that in The Bible, and in England, the term "vine" is exclusively used in
reference to the grape vine and the English use the word "climber" as Americans use the word "vine".
The Physiological Characteristics of Vines
Most vines lack the fibers surrounding the nutrient canals (xylem and phloem) that enable stronger plants
to remain upright without support. The xylem and phloem also tend to be enlarged and separated by
photosynthetic storage tissues. This gives a vine its suppleness and ability to convey large amounts of
water and nutrients. It further allows for the fast growth needed to reach the top of the canopy and gives
the stems the flexibility to withstand the inflexibility of its host without kinking the stem. Another strategy
to keep the stems from kinking is flattened stems or cross shaped stems as exemplified by Cross Vine
(Bignonia capreolata). There are also several structural modifications that vines use to enable them to
climb such as thorns, tendrils, hooks, discs, pads on tendrils, and adventitious rooting.
Types of vines:
There are many ways to further categorize this unruly group of plants and as diverse as this group is, it
must be realized that the general categories listed below are purely artificial groupings of plants based on
superficial characteristics. Vines as a whole are not a scientifically ordered group of plants but are a loose
assemblage of plants with common features.
Lianas
Woody perennials with rope like stems that climb up to the crowns of trees. Most have stems bare of leaf and flowering and fruiting generally takes place only at growth tips at the tops of the trees. Most lianas are too large for the garden. Solandra maxima is an example of this type of vine.
Scramblers
Woody or tough herbaceous plants that spread over other vegetation into a tangled mat - Lack the strong upward pull of the lianas. Ipomoea is an example of this type of vine.
Climbers
The middle ground between the lianas and the scramblers - Lack the heavy woodiness of the former but
have a strong pull toward the heavens - the plants that we typically think of as "vines' fit best into this
category.
Climbing Strategies
Apart from the a vine's classification "type", there are many different strategies that vines use to climb and hold onto objects.
Leaners
These plants a really shrubs that exhibit vining characteristics. They grow vertically but lack many of the
means to stay erect as they will not cling and support must be provided to obtain much height.
Tecomaria, Allamanda, Grewia are all examples of this "type" of vine. In nature these plants grow through or over others and in the garden a trellis or similar structure is needed
Thorn Clingers
Separated into 4 categories from weakest to strongest with examples
Stem Prickles
These plants climb by grasping other foliage with rough edges on their stems. Lantana climbs by this method.
Substantial thorns
These plants are not specialized for climbing but the thorn prevents plants from backsliding. Bougainvillea and Rosa wichuriana hold themselves up by this means.
Recurved Spines
These plants have a recurved stipular spine that holds fast to anything it contacts. Rosa
laevigata, Pereskia species exhibit this characteristic.
Armed Whips
This unusual group of climbing plants have leaves that end in vicious armed tips. Rattan palms are so armed.
The Graspers
Structural modifications enable these plants to grasp a support and hold on. A majority of vines fall into this category of which there are three types with a great deal of overlap. For example Parthenocissus; it is a tendril clinger that develops adhesive cushions if against a wall
The Twiners
This group of graspers has tips on the new growth that twist around objects. These twiners often grow out in circular manner (circumnutation) but contrary to popular belief, there is no relationship between right vs. left directional twisting as a function of being in the northern or southern hemisphere. It has been found that 95% of direction of growth is constant to species and the others move in the direction that opportunity offers. Pole beans, Ipomoea, Wisteria, Mandevilla,
Stephanotis, Lonicera, Jasminum, Solanum and
Aristolochia are all examples of these simple twiners. Some in this category have touch sensitive tissues such as those of Clematis whose leaf tissue reacts to friction, causing petioles to curl around the cause of the friction. Maurandia and Rhodochiton react in similar manner
The Clingers
These graspers have weak tender flexible organs called tendrils that respond to friction by grasping or adhering to objects. Once tendrils have become attached, their tissues develop to increase in strength and the tendrils coil back toward the plant from contact
point with the coil reversing direction in between, making an springy connection between plant and support. If a tendril fails to attach or is pulled loose it will generally wither and
fall off. Additionally tendrils can swell in openings or wrap thinner contact points. These specialized tendrils can be modified stems, such as in Antigonon, modified stipules such as in Smilax, true branches such as in Passiflora, a leaf opposed tendril growing developing from modified terminal growth such as the grape, a terminal leaflets modified into single tendril as in Clytostoma, into branched tendrils such as in Distictis, into trifid tendrils such as in Pyrostegia or even into tripartite tendrils as in Pithecoctineum. Some of
these tendrils may be negatively phototropic allowing them to search out crevices for support or have the tips forming large balls of tissue with a mucilaginous surface that
adhere to nearly any surface.
The Rooters
These vines develop roots at each node as they grow. Often these plants are groundcovers until they reach vertical means of climbing. They can bury roots into the bark of trees or into structures. Ficus pumila, Hedera species and Hydrangea petiolaris are all examples of this type of climber
Miscellaneous Vine Facts
- 90% of all vines come from 10 families Connaraceae, Fabaceae, Apocynaceae, Menispermaceae, Bignoniaceae, Acanthaceae, Asclepiadaceae, Passifloraceae, Cucubitaceae, Convolvulaceae
- The plant Iochroma in California is a shrub - in England it becomes viney
- Not only are the stems flexible but often so is their strategy a vines exhibit a different method of climbing different situations i.e. the lack of tendrils when Pyrostegia is twining on chain link vs. clambering over other surfaces
- Most vines are dicots but a few are monocots that without the cambium producing stems are usually lighter and less voracious - exception being the rattan or climbing palms which are among
the most massive stemmed "vines" in the world. The tropical American climbing palm (Desmoncus) has been measured at 3,000 feet in length in Costa Rica. Other monocots include Asparagus, Gloriosa, Bomarea, & even some grasses can be considered to climb (Arundo donax, Cynodon dactylon, Chusquea coronalis
- The name Wisteria,, which is both the common and the scientific name for the beautiful Asian vines
so popular in our gardens, commemorates an American, Caspar Wistar and the misspelling of the name has been retained because it was first described as such. Although the better know plants
are the Chinese Wisteria and the Japanese Wisteria there are 2 American species little known in cultivation. W. frutescens ranges from Texas north to Virginia and W. macrostachya has a similar
range but reaches only as far east as Tennessee.
- The passion flower (Passiflora sp.) is so named because a seventeenth century monastic scholar felt it to be his duty to tell the world of a flower that not only represented the cross of Christ but also the other mysteries of the passion - the crown of thorns (corolla filaments), the 3 nails (the stigma and the columns of the flagellation as they appear on ecclesiastical banners (the androgynophore - stigma tube). The base of the androgynophore is a gold color with 5 red spots representing the five wounds received by Christ. There are 72 filaments, which according to tradition is the number of
thorns in the crown of thorns. The lance shaped leaves represent the spear that pierced his body
and the underside of the leaf is marked with dark round spots representing the 30 pieces of silver
that Judas was paid to betray Christ.
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