An Adventure of Growing Madagascar Lace

One of the most exotic and unbelievably beautiful plants in all of Plantae is the Madagascar lace plant. Conspicuous for its lacy, or fenestrated leaf appearance (Latin base word for window – fenestra), Aponogeton Madagascariensis is a fully aquatic bulb plant that is endemic to shallow, cool and shady streams of Madagascar. These monocots begin life as tiny green seeds that form on double flower spikes emerging above water to attract pollinators, dropping into the water and taking hold in the streambed where they slowly grow into bulbs, or more specifically rhizoming corms. If given a chance these eventually form large rosettes of leaves that undulate in the natural current. Prized as the king of the aquarium plants, wild populations were once severely threatened by over collection by the trade, before conservation and better commercial cultivation eased that pressure in recent times. I seem to remember these streams having an abundance of limestone and basalt, perhaps thus some carbonic action, Co2 and a rich mineral supply. Out of many natural varieties or subspecies in habitat there are two main varieties in cultivation, from what I can see: a long leaf variety and a wide leaf variety (var. Major) that appears to have just veins and no leaf skin. But several publications have me looking for clarity and an elusive third variety.

The Madagascar plant caught my attention in a field guide back in college and I swore I’d someday try my hand at growing this legendarily difficult jewel. Its reputation as highly challenging is somewhat justified because of the many specific environmental conditions it requires to thrive and not languish in a typical home aquarium system. Why can’t something so cool be easy, for once? Laceplants, like irises and lilies, have a seasonal rest period, or dormancy, during which the corms produce tiny leaves or even cease production of leaves. The dormant period for this cool water-loving plant is in the warmest months. It also likes lower light levels such as that provided by 30 or 40 percent shade cloth in South Florida where I grew them. Unwanted algae, the bane of aquarists everywhere, is the greatest hazard to the laceplant’s ability to photosynthesize and charge the bulbs, because it grows all over the limited surface area of the veined leaves if not kept in check by proper nutrient balance, clean cool water with a constant gentle flow and natural means of algae suppression. In the home tank or pond, what usually happens is that the bulb puts out leaves in a captivating blaze of glory for several months. Then it sheds increasingly senescent (often algae-blighted) browning leaves, goes dormant and rots, having been literally emptied of bulb “fat” without the benefit of a recharge. To prevent this, they greatly benefit from the addition of carbon from Co2 diffused plentifully and efficiently into the water column on a constant basis.

My first attempt in 2000 started out well advised by conventional wisdom and then-current pro advice, in a 40 gallon breeder tank cooled to 68-70f by a drop-in coil chiller, Co2 diffusion, a submersible pump for water circulation, substrate cable heater, iron laterite clay/gravel with no organic/humic soil. I dosed potassium, chelated iron and some kind of organic “tea” for planted tanks. It was illuminated by two powerful metal halide pendant lights. My snazzy rig turned into an expensive failure. After four months, the bulbs went dormant and rotted after some flowering and seed starts. I know now I shouldn’t have let the chiller run during dormancy, and the lack of soil, a stronger water current and mineral micronutrients also hurt. If I had put in a lot more Co2 and used some soil below the gravel, these might have had a chance. All were dead by six months.

My next try on a larger scale in 2016 however was a pioneering success. This time, an eight foot, 650 gallon kiddie pool under an old orchid grower’s shaded pergola in S.W. Florida was my lab. I researched the heck out of Aponogeton Madagascariensis, its habitat and grower’s clues gleaned from the web. I ditched the sterile laterite for a mix of mostly Miracle Gro garden soil and some laterite under a thick layer of black basalt gravel of high micronutrient content (Eco Complete), then added a laceplant bulb to each shallow gallon pot. Keeping a moderate current going throughout the pool was easy with two clip-on impeller fans and a pond pump in the center into which the Co2 diffuser with UV sterilizer were linked. The shade and ambient ground temperature kept the pool cool enough most of the year. I kept a rotation of decaying barley straw bales in front of an impeller at a sunnier end of the pool to inhibit algae growth. The addition of a planted square side pool (refugium) flowing into and slightly higher than the main pool was a big breakthrough in consistent water quality. Green Leaf Aquatics powdered macronutrients and LOTS of chelated iron, micronutrients dosed regularly while the planted refugium to buffer against overdosing did the rest.

This combination of ideal conditions, better equipment, nutrients and overly generous Co2 diffusion gave me mind-blowing results and several proprietary innovations for growing two subspecies from seed. For the two-plus years the system was running, my Madagascar laceplants grew into almost four foot monster rosettes in heavy bloom most of the time, and there was no complete dormancy. I learned to efficiently harvest and grow seeds from the brush-pollinated flower spikes. Corms divided into multiple rosettes on mature plants and I was growing about 2000 baby plants in gel shot cups. The experiment yielded a ton of valuable data and gave me what is essentially mastery of the laceplant. Even the eventual destabilization and failure of the system produced valuable knowledge.

Sometimes good things come to an end. The lacepool in its height of green patterned glory was a sight to behold. The rectangular side refugium stuffed with cattails and dollar weed that circulated and cleaned the pool water, while it lasted, worked well to cut down on algae. What I didn’t realize was that beneath all of the leaves on the surface I had a gradual, undetected time bomb buildup of decaying spent leaves that caused a massive nutrient overload one warm Spring week that resulted in a sudden chronic algae bloom. Controlling phosphorous is the key to algae control, though a little is vital for plant growth, and dead plant material puts way too much back into the water column. Phosphorous remover dosed weekly sometimes helped but the shade from an overabundance of healthy leaves in a limited sized pool (and space and budget), accumulating muck and rampant algae slowly stunted or killed the younger plants before they reached sellable size. Shortly after this decline began, we moved before I had a chance to recover by building a better refugium, adding a large colony of Amano shrimp for algae control and some fence mesh to keep critters like raccoons with a taste for shrimp out.

My main mistakes: not having algae-eating shrimp, not removing spent leaves and muck, not having separate ponds for small seedlings and large breeding plants, and finally, removing the beneficial cattails that were nonetheless slowly ripping apart the homemade refugium I’d built and plumbed from scrap. A linear “river” pool next time with drop-through grating beneath the pots might ferry away the dead leaves by flow suction into a convenient catchment for humification or pool net removal, maybe even cycling under a banana mat bed and flowing inside a giant cactus greenhouse to double as thermal mass against low Winter temps. The point of a closed system is natural balance without having to use an armada of chemicals, and for a long while I had achieved this. Notes were taken and saved.

The move from to N. Florida further stressed the plants and the young seedlings never recovered after a couple of winters without a substantial reinvestment in equipment. That heavy, damaged refugium had a curbside funeral the week before we moved as it was not coming with us. I had them in a holding pattern of maintenance while we scrambled like mad to restore the house, build a greenhouse, create food beds and weed the land of invasive weeds and buried trash. Most of the Asian Cryptocoryne plant baskets and a few parent lace bulbs are what remain in the pool. I’ve also put most of my effort into all of the cacti after waves of unexpected fruit and seeds presented the opportunity, but I will return with a vengeance to growing the laceplants in a safer, more stable system when I erect the big high tunnel. For now, at least I’m less likely get electrocuted by aging submerged pumps and impellers while tending the cactus.