Florida’s giant air plants (Tillandsia utriculata) have been under attack for over three decades by an invasive pest called the Mexican bromeliad weevil (Metamasius callizona). The weevil, accidentally introduced into Florida in 1989, chews holes in the leaf bases of the bromeliads, then lays its eggs. As the larvae feed and mature, they eat the base, mining into the stem and often kill the plant. Unfortunately, these long-lived giants can take more than 10 years to flower. Unlike most bromeliads, they don’t produce vegetative offsets after blooming. If they get weevil-attacked before flowering, they are lost, unable to produce seed.
Selby Gardens is working to better understand the life history of giant air plants by studying how long and under what conditions seed can be stored, how fast they grow, and at what age they flower. Seedlings germinated for this work back in 2015 are now ready to transition to the next phase of monitoring–that means living in the great outdoors or “in the wild!”
In late March, staff botanist Liz Gandy, together with her schooling-from-home-son, set out to plant baby giant airplants in five locations on Selby Gardens’ Downtown Sarasota campus grounds. At each site, five seedlings of known age were glued to preferred host trees like live oak (Quercus virginiana), southern red cedar (Juniperus virginiana), and green buttonwood (Conocarpus erectus). Five sets of counterparts of the same seedlings were simultaneously housed in the Tillandsia greenhouse for comparison. Moving forward, the seedlings from all sites will be measured regularly to determine growth rate “in the wild,” and under greenhouse conditions. Currently the average size of these young Tillandsias is 44 mm (less than two inches); and since they can grow to three-quarters of a meter long (two feet) at maturity, this will be a long-term project for sure!
Written by Elizabeth Gandy, Botany Curatorial Assistant