Many of the Mexican petunia plants, Ruellia simplex, growing in the landscape along the Gulf Coast are covered in white patches. The leaves appear to be growing fur, actual hairs, much denser than the dust of powdery mildew fungus. Excessive development of leaf trichomes, or surface hairs is referred to as erinea. The “fuzz” is the plant’s response to the feeding of eriophyid mites, also called gall mites. These native tiny, microscopic mites feed on the Mexican petunia leaves and stems, causing the plant to produce the white velvety masses. The distorted tissue provides shelter so the mites can continue to feed without being impacted by the weather or contact pesticide applications. Hot, dry conditions favor mite population increases. We have had plenty of that. However, the native mites are not likely to kill the invasive Mexican petunia, so they are not acting as an effective biological control for the plant.
Mexican petunia damage from the eriophyid mite.
Control of this native eriophyid mite begins with heavy foliage removal. Cutting the plants back to just a few inches above the ground removes the infested portion of the plant. The pruned parts need to be placed in a tightly sealed plastic bag before being sent to the landfill. If the location allows burning on-site, that is an even better option. Remember that these mites can feed on many other plants if allowed to escape. They have caused galls in crape myrtle, loropetalum, and hollies, as well as, vectoring diseases like rose rosette.
Then comes the tough decision. If the Mexican petunia is not one of the new sterile cultivars should the new growth be protected as it grows back? If you didn’t plant them or don’t remember what they were called when you purchased them, there is still a way to determine whether they are the invasive Mexican petunia or not. Invasive Mexican petunia produces seed after flowering. Were there any seed pods on the pruned parts? If so, you may consider killing off the entire planting. Several applications of a total vegetation herbicide with surfactant will remove them, leaving you a spot for a new purple flower, maybe a porterweed (Stachytarpheta), verbena or blue salvia.
Blue porterweed can be a substitute for non sterile Ruellia. Photo by Beth Bolles UF IFAS Escambia Extension
If your plants are sterile (have no seed pods), an application of horticultural oil and/or a miticide like abamectin sprayed with each flush of new growth will produce a pretty bed of purple flowers in a short period of time.
The UF/IFAS Extension Northwest District Horticulture Team is excited to announce our third season of Gardening in the Panhandle LIVE! free webinars! Please plan to join us this Spring and Fall for all new episodes where we will tackle gardening issues relevant to the Florida Panhandle!
There are two ways to join the Gardening in the Panhandle LIVE! webinars:
Facebook Live – Follow us on Facebook and follow individual webinar Events.
Zoom Webinar – Pre-registration is required for Zoom. Users must have an authenticated account (free at Zoom Link). Be sure you have security settings up to date to prevent connection delays. Links to Zoom registration will be added to the topic one-two weeks before the webinar and a closed captioned recorded link to YouTube will be available approximately one week after the program. (Underlined words have active links!)
Although we do accept questions from the audience during the broadcast, we may not have time to read them on-air. If you have a great question you think other viewers need to hear, please pre-register through Zoom and submit early!
All webinars are on a Thursday at Noon CDT/ 1:00 p.m. EDT
Looking to add something to brighten your landscape this autumn? Firespike (Odontonema strictum) is a prolific fall bloomer with red tubular flowers that are very popular with hummingbirds and butterflies. Its glossy dark green leaves make an attractive large plant that will grow quite well in dense shade to partial sunlight.
In frost-free areas firespike grows as an evergreen semi-woody shrub, spreads by underground sprouts and enlarging to form a thicket. In zones 8 and 9 it usually dies back to the ground in winter and re-sprouts in spring, producing strikingly beautiful 9-12 inch panicles of crimson flowers beginning at the end of summer and lasting into the winter each year.
Firespike is native to open, semi-forested areas of Central America. It has escaped cultivation and become established in disturbed hammocks throughout peninsular Florida, but hasn’t presented an invasive problem. Here in the panhandle, firespike will remain a tender perennial for most locations. It can be grown on a wide range of moderately fertile, sandy soils and is quite drought tolerant. Firespike may be best utilized in the landscape in a mass planting. Plants can be spaced about 2 feet apart to fill in the area quickly. It is one of only a few flowering plants that give good, red color in a partially shaded site. The lovely flowers make firespike an excellent candidate for the cutting garden and is a “must-have” for southern butterfly and hummingbird gardens. Additional plants can be propagated from firespike by division or cuttings. However, white-tailed deer love firespike too, and will eat the leaves, so be prepared to fence it off from “Bambi”.
Bulbs are my favorite class of ornamental plants. They generally are low maintenance, come back reliably year after year, and sport the showiest flowers around. While many bulbs like Daylily, Crinum and Amaryllis are very common in Panhandle landscapes, there is a lesser-known genus of bulbs that is well worth your time and garden space, the Rainlily (Zephyranthes spp.).
Rainlily, aptly named for its habit of blooming shortly after summer rainfall events and a member of the Amaryllis family of bulbs, is a perfect little plant for Panhandle yards for several reasons. The plant’s genus name, Zephyranthes – which translates to English as “flowers of the western winds”, hints at the beauty awaiting those who plant this lovely little bulb. From late spring until the frosts of fall, Rainlily rewards gardeners with flushes of trumpet-shaped flowers in shades of white, pink, and yellow, with some hybrids offering even more exotic colors. While these individual flowers typically only persist for a day or two, they are produced in “flushes” that last several days, extending the show. Though Rainlily flowers are the main event for the genus, beneath the blooms, plants also offer attractive, grass-like, evergreen foliage. These aesthetic attributes lend themselves to Rainlily being used in a variety of ways in landscapes, from massing for summer color ala Daylilies, to use around the edges of beds as a showy border like Liriope or other “border” type grassy plants.
Unknown Rainlily species blooming in a raised bed. Photo courtesy of Daniel Leonard.
Continuing along the list of Rainlily attributes, the genus doesn’t require much in the way of care from gardeners either. Most species of Rainlily, including the Florida native Z. atamasca, have no serious pests and are right at home in full sun to part shade. Once established, plants are exceedingly low-maintenance and won’t require any supplemental irrigation or fertilizer! Some Rainlily species like Z. candida even make excellent water or ditch garden plants, preferring to have their feet wet most of the year – putting them right at home in the Panhandle this year. And finally, all Zephyranthes spp. do very well in containers and raised beds also, adding versatility to their use in your landscape!
The one drawback of Rainlily is that they can be somewhat difficult to find for sale. As these bulbs are an uncommon sight in most garden centers, to source a specific Zephyranthes species or cultivar, one is probably going to need to purchase from a specialty internet or mail-order nursery. As with other passalong-type bulbs though, the absolute best and most rewarding way to obtain Rainlily is to get a dormant season bulb division from a friend or fellow gardener who grows them. There are many excellent unnamed or forgotten Zephyranthes cultivars and seedlings flourishing in gardens across the South, waiting to be passed around to the next generation of folks who will appreciate them!
Even if you must go to some lengths to get a Rainlily in your garden, I highly recommend doing so! You’ll be rewarded with years of low-maintenance summer color after the dreariest of rainy days and will be able to pass these “flowers of the western wind” on to the next gardening generation. For more information on growing, sourcing, or propagating Rainlilies, check out this EDIS publication by Dr. Gary Knox of the UF/IFAS North Florida Research and Education Center (NFREC) or contact your local UF/IFAS Extension office! Happy Gardening!
‘Stellar Ruby’ is a new purple-flowered hybrid banana-shrub that will soon be released nationally
You just learned about a fabulous new plant, and you HAVE to have it. How can you acquire this rare treasure?
Many of us gardeners have experienced this desire for a “new” plant but have quickly become frustrated with trying to locate and buy that particular plant. It’s not easy, or else that plant wouldn’t be new or rare, but the four P’s outline a few strategies for satisfying a “new” plant passion: plant societies, plant institutions, patience and payment.
Plant societies are one of the best avenues for acquiring new plants. Most plant societies consist of members with intense interest in particular plants or plant groups, so find the society that supports the plant that interests you. Plant society members often include breeders or plant explorers who introduce new plants. Whether magnolia or camellia or conifers or other plants, membership in such societies can give you a leg up on learning about, seeing, and accessing new plants. Consequently, fellow society members are often the first to acquire the newest plants, and that could be you!
Beyond this, participation in generalist plant groups can also give you unexpected benefits of networking with like-minded people. Thus, don’t overlook groups like Master Gardeners, garden clubs, or garden/park support groups. Their members often include passionate plant people like you who may have more connections (or special plants) than you realize.
Similarly, plant institutions such as universities or botanic gardens are another way to learn about and acquire new plants. These institutions often hold plant sales or fund-raising plant auctions that include new, unusual or rare plants. Online plant sales or auctions are becoming more common, so distance is less of an obstacle than it used to be. However, these institutions are less focused on particular plants, so it may be hit-or-miss to find that particular plant you want. To increase the chances of finding your desired plant, contact these institutions and ask to be notified about these events. You may even find a plant you didn’t know you wanted!
Patience is a virtue when trying to acquire new plants. Some plants take a long time to propagate or are not easy to propagate or grow. If you have the patience to wait, many plants will become more available – – – and at a more reasonable cost – – – as nursery production catches up to demand.
Finally, “payment”: let’s face it, money talks! If you have the funds, you can usually find the means to acquire the plants you desire. Most new or rare plants usually enter the market through specialty nurseries, operations that often maintain their own breeding or plant exploration programs or have exclusive arrangements with those who do. This is an expensive means of obtaining new plants, and therefore these specialty nurseries rightly charge more for their plants.
Another way money works to your advantage is the ability to travel. Many specialty nurseries, collectors, etc. often aren’t found in our part of Florida. If you can travel to these nurseries, botanic gardens, etc., it will be much easier to acquire unusual plants. If you can’t afford special trips to these sites, consider taking vacations to areas near these specialty nurseries, or to areas where these specialty nurseries are “on the way” to your vacation destination.
It goes without saying that you should learn about a “new” plant as much as possible before investing in an extensive hunt. Simple internet searches should tell you if that plant will be adapted to the climate and soil of your garden. At the other extreme, check resources like the IFAS Assessment (https://assessment.ifas.ufl.edu/) to make sure that particular plant won’t become invasive in your region of Florida.
Gardening is a very fulfilling activity, and the excitement of “new” plants just makes gardening more fun! Happy hunting!
