Tuesday, January 14, 2014

Horticultural "Hassles"

Most botanic gardens pride themselves on collections that are not only interesting, but aesthetically beautiful as well. This emphasis on beauty is a higher priority for gardens whose main focus is display and horticultural excellence (e.g. Longwood Gardens) than for gardens focusing on research and conservation (e.g. Montgomery Botanical Center), which may have limited public exposure. Botanical gardens with education as the highest priority usually fall somewhere in the middle because they want to have interesting specimens whether or not they are especially "showy," but at the same time, aesthetic beauty makes the gardens much more attractive to the public. This is the case at The Botanic Gardens at Kona Kai Resort, as we do want our focus to be on developing a collection of the most interesting ethnobotanical specimens that can grow in our climate to serve our educational mission, but at the same time the Gardens is on the grounds of a small high-end resort, which of course needs to look as amazing as possible for as much of the year as possible.

Ethnobotanical and elegant.

Fortunately, we have an excellent Grounds Director in Veronika Milar, who makes sure things are always as picture-perfect as possible when you walk into the Gardens, but we still encounter many of the same issues that gardeners throughout southern Florida and the rest of the world deal with on a regular basis. People seem to think there's some sort of magic that horticulturists and their crews at botanic gardens have to keep everything looking so good, but it really boils down to knowing your plants, the tools of the trade, the characteristics of the local environment, and the organisms that interact with your plants. After learning this information, horticultural success is almost directly proportional to the amount of work put into a garden based upon observations of the collections. Aesthetic beauty is also greatly enhanced with expression of the horticulturist's artistic side.

You can find Veronika hard at work in any of our garden areas; here she is trimming back ixora by the parking lot.

Ileana is one of Kona Kai's expert housekeepers, but she also spends time in the gardens helping Veronika out.

Veronika next to one of her most recent artistic masterpieces at Kona Kai - the Aquascape Garden, which she completed last summer.

But lest you think it's all about knowledge, pruning, and art, you might be surprised to know that in our peaceful setting, war is being waged for control of the Gardens on many fronts, with a variety of weapons and strategies implemented by all involved. If they had their way, all sorts of plant pests would be devouring our plants, making them quite unsightly and even taking their very lives. Obviously, it wouldn't be a good idea to offer up our collections as an all-you-can-eat buffet for these creatures. Fortunately, most plants have developed some chemical or physical defenses on their own to fight pests and diseases, but sometimes these defenses aren't sufficient to preserve their aesthetic integrity or their lives, especially when it comes to pests and diseases they've never encountered before. Horticulturists (expert gardeners) are the reinforcements plants often need to not only survive attacks by these enemies, but be overwhelmingly victorious. A notable pest that we, along with much of the rest of southern Florida, have been dealing with recently is the spiraling whitefly:

As you can see, it makes quite a mess out of the leaves, but it doesn't end there - the little white flies exude a sticky sweet secretion that falls on whatever is below the trees and becomes infected with sooty mold, covering the understory with a delightful sticky blackness. Just as we were making some encouraging headway against this critter, another hardier foe, the croton scale, stepped in to take its place:

Lovely! The sooty mold seems to enjoy the secretions of this pest, too!

Not all of our pests are tiny - iguanas have become our main macroscopic herbivorous foe. Having exploded in population over the past several years, they find various flowers (hibiscus, orchids, etc.) and leaves quite tasty and can devour much of a plants vital photosynthetic and reproductive parts if we do not deter them. As thanks for allowing them to browse our beautiful plants, the iguanas kindly deposit their digested remains throughout the Gardens, often raining them down from tree branches. Needless to say, we are constantly cleaning up after these uninvited guests.

Don't even think about it!

Sometimes, it's the enemy you cannot see that is the most dangerous and hardest to fight. Several years ago, lethal yellowing (a microscopic phytoplasma) was spreading rapidly from palm to palm via leafhopper insects, killing the palms in only a matter of weeks, despite a variety of attempted human interventions. While there was much effort to contain the spread of the disease, there was also a great effort to develop a preventative antibiotic, which when injected into the trunks of palms, protected them from the phytoplasma. This ended up being very effective at stopping the spread of the disease, and fortunately, it hasn't been seen again in the area for a number of years.

Photo of lethal yellowing symptoms in coconut palm (Cocos nucifera) by N. A. Harrison, University of Florida.

Site of the antibiotic injection into the trunk of one of our coconut palms.

Fungus is also a particularly troublesome foe. Whenever we have a particularly rainy period, fungi grow particularly well, and we keep close watch over our cacti, orchids, and other plants that may be particularly susceptible to fungus, such as rosy periwinkle. Unfortunately, there's not much one can do to save a plant after it's been infected by a fungus, but there are some preventative means we can take, like planting susceptible plants in substrate with very good drainage and applying fungicide if things get desperate. Despite all our best efforts, sometimes the enemy wins out in the end, as has been the case with our rosy periwinkles:

Beyond pests and diseases, we also need to be conscious of environmental factors that affect plant health, such as soil conditions, nutrition, temperature, sunlight, and water. Botanic gardens such as our own often acquire plants native to a variety of areas around the world, so it is sometimes difficult to get a plant to grow in an area that is not perfectly suited to its preferences in these areas. This is where knowing your plants and their needs is invaluable.

This would be a puzzling condition if you didn't know that ixora turn chlorotic in basic soils (which we have in the Keys). Any time we see this, we add a fertilizer that increases soil acidity (similar to rhododendron care).

Natural disasters are another variable for horticulturists. We just so happen to be in a pretty high-risk area for natural disasters, namely hurricanes. In contrast to many of the other challenges horticulturists face that we have discussed, there is little one can do in the face of an impending natural disaster. While wind damage will often have the highest impact on the collections, flood damage is also a possibility; not many plants are too happy about having their roots submerged in salt water.

Wilma gave the Keys their most recent walloping.

If a plant ends up suffering or dying because of one of these factors or simply dies because it reaches the end of its lifespan, I keep notes of all this information for each particular plant in the Gardens' BG-Base plant database. There are often quite a few plants to replace any given year, so to prepare for these inevitable occasions, I keep a list of interesting ethnobotanical specimens we'd like to see in the collections should we have an opening.

Basically, after considering all these things, I see two ways of looking at garden maintenance: 1) It's a never-ending hassle you can never win at, full of things that go "wrong" that you have to "deal with" or 2) It's an endless number of interesting challenges that keep you on your toes, always learning and experimenting, having fun puzzling things out and trying different solutions. I personally feel the latter perspective is much truer to the spirit of gardening: it's supposed to be stimulating rather than stressful. Nature is death constantly giving way to new life; why should we expect anything else in our gardens? So the next time you see another pest in your garden or another plant succumbing to some unknown ailment, don't get upset/angry/frustrated, but rather get excited about learning more about the natural world and developing creative solutions to try out. Worst-case scenario if a plant dies is you have the opportunity to shape the garden anew and an excuse to go shopping for new and different plants!

Rick Hederstrom
Associate Director