Snake plant flowers

It is hard to believe that anyone has not at some time had snake plants (Sansevieria) in their family households. The ability of this interesting but strange plant to survive almost any treatment made it popular around the world as a house plant. Unfortunately in warmer areas such as Florida they ended up planted outside and have caused considerable problems since they are highly invasive, especially in shaded forest locations where native plants are crowded out by the snake plant. Removing them is problematic since the roots break into small pieces and generate many new plants.

I have fought a running battle with snake plants in our Florida yard since a former owner got them started. So I always considered them a big pest with no redeeming qualities. However I have now recognized that the regular Winter-time blooms of these plants are actually quite interesting from an ecological perspective (see photo). A spike of white tubular flowers emits a powerful fragrance and is actually quite beautiful, if you can get past the bad-boy image of this species. I am always interested in predicting what might pollinate specific flowers, based on flower color, shape and smell. I found out that this plant originated most likely from Western Africa but have not yet found out what pollinates it in its native habitat. However the white tubular flowers with a strong odor indicate pollination by a night-flying moth with a long tongue, possibly a sphinx/hawk moth whose larvae are often called horn worms.

I did find one article that determined that the primary sugar in the nectar of the common snake plant is sucrose, and predicted that this in conjunction with the flower structure would attract mainly sphinx moths. Note also that the authors found extra-floral sources of nectar and surmised these might satisfy creatures such as ants that might otherwise steal the flower nectar and limit the plant's ability to reproduce:

http://aob.oxfordjournals.org/cgi/content/abstract/58/4/541

So look around you with a renewed interest in plants and animals that you might have dismissed as unworthy of notice, and you may find unsuspected beauty and interest among the "bad boys" of the natural world.

Bill DunsonEnglewood,

FL & Galax, VA

The problem with plumbago- how to think like a butterfly

In our desire to provide sources of nectar for insects, we often are tempted to plant exotic plants which can provide beautiful flowers for the garden and hopefully nourish some of our "flying flowers", the wonderful butterflies. It is not always obvious how to balance native and exotic plants in the garden since certainly one would prefer to use native plants whenever possible. However natives may not always flourish in a given place, and they may not provide abundant flowers at all times of the year. Of course many of us inherited plants in our gardens when we purchased a house and find it difficult to remove flourishing but perhaps non-productive flowering exotics. One problem I face in our yard is that of plumbago, the shrub from S. Africa that is widely planted in Florida, Texas and California. It has pretty blue flowers, blooms profusely and is non-invasive. So is it a "good exotic" to have in the garden? The answer is NO ! But the reason may surprise you- not just because it is an exotic but because its the nectar in its flowers is not available to most insects in N. America. Look at the attached photo I took in our yard of a honeybee hopefully checking out the plumbago for a quick lunch- but to no avail. The problem is that the corolla tube, where the petals are fused into a long tubular structure holding nectar at the bottom, is very long relative to the length of the tongue or proboscis of the bee, or almost any other local insects. Thus they can look but not drink! So this flower is essentially useless as a provider of nectar for butterflies. In its native S. Africa it is known to attract butterflies and to act as a larval food plant. Some birds have figured out a solution to this problem by piercing the base of the flowers and "stealing" nectar.

Another common example of this problem with long corolla tubes is Ixora, the beautiful red tubular flower from India. Once you recognize this situation you can now examine your garden for unproductive flowers, at least from the perspective of hungry nectivores. This will require a fundamental change in your perspective about your garden- to carefully re-examine all of your plants on the basis of their usefulness to butterflies. So get out there and watch each of your flowers and see if the butterflies are actually able to feed from them.

Bill Dunson