There are over 400 species of tropical and sub-tropical passion flowers (Passiflora sp.). These vigorous vining plants are recognized for their exotic, ten-petaled, sweet smelling flowers. Although they originate from South America, passion flower vines have naturalized all over the tropics. Some passion flowers produce highly valued fruit, too, which is used for juices and desserts. Unfortunately, passion flower vine problems are common. Read on to learn what these may be and what can be done about it.
Passion Flower Vine Problems
All passion flowers are frost tender. They must be protected in the winter. They are also susceptible to soil borne diseases, fungi, viruses, bacteria and nematodes.
One of the issues affecting passion flower vines is that the sweet tasting, purple fruited subspecies is highly susceptible to the root knot nematode. Root knot nematode causes a severe thickening of the roots and even death. Fortunately, the more acidic, yellow fruited subspecies is resistant to nematodes and can be used for root stock and disease resistant hybridization.
There are many passion flower diseases. One of the biggest problems with passion flower is the fungus that causes fusarium wilt. Fusarium wilt is a soil borne disease that can be deadly. The first signs are yellowing leaves followed by dying and dropping leaves. After that, the branches and trunks split and come away from the bark. Finally, the roots discolor and die. Again, growing passion vine on the yellow fruited subspecies root stock helps control this problem.
Viruses, like cucumber mosaic, can affect passion flower vines. It is commonly transmitted through cucumber beetles and aphids. The virus can also spread between plants or infected seed. Plants that are affected show a mosaic type mottling in the leaves along with stunted growth and leaf distortion. There is no cure other than prevention, so infected plants should be removed.
Pests of passion vine also include the highly damaging bacterial spot caused by the bacteria Xanthomonas. It is very difficult to control and causes a lot of damage to commercial crops. The disease begins with small round spots on the leaves. These spots can grow larger, kill the leaves, reduce photosynthesis, enter the vascular system, reduce plant vigor, damage fruit and even decimate the whole plant. There are no chemicals on the market that will control this disease. Some species have shown limited resistance and there is hope that a resistant variety that also produces good fruit can be developed.
Passion flower vine is a highly attractive and, in some cases, edible plant. But it is important for gardeners to be prepared for passion flower vine problems. Buy only disease resistant species. Plant them in the right spot with good quality, fast draining soil in full sun with humid air and plenty of water. This should help these plants resist most disease and pests of the passion vine.