Pinguicula Mexican Butterwort

Mexican butterwort, most commonly sold under the Pinguicula moranensis complex, is a small, tidy carnivorous rosette that looks like a pastel houseplant and behaves like a very patient flypaper trap.

The leaves sit flat in a circular arrangement, soft to the touch, and coated in a clear, sticky layer made of mucopolysaccharides, which are long-chain sugars that behave like biological glue. Insects land, get stuck, and are slowly dissolved by enzymes secreted directly from the leaf surface.

Nothing snaps shut, nothing lunges, and nothing dramatic happens unless you are a fungus gnat having a very bad afternoon. This plant prefers bright indirect light that is strong enough to maintain leaf color and stickiness without scorching the surface, consistently moist but extremely low‑mineral substrate, and water that does not quietly poison it over time. Despite the carnivorous label, it is non‑toxic to pets and people.

The digestive enzymes only activate in response to trapped prey and are designed to break down insect proteins, not mammal skin, tongues, or curious noses.

Mexican butterwort care is less about feeding drama and more about restraint, light discipline, and respecting the fact that this plant evolved to survive where soil offers almost nothing.

Treated properly, it stays compact, colorful, and quietly effective without turning your home into a swamp or a science experiment.

INTRODUCTION & IDENTITY

At first glance, Mexican butterwort looks like something you would expect to see labeled “easy-care pastel succulent” at a home décor store.

The leaves are smooth, slightly glossy, and arranged in a neat rosette that practically begs to be touched. Touching it will not hurt you, but it will leave your fingertip slightly tacky, which is the first clue that this plant is not as innocent as it looks.

While you are washing your hands, it will be slowly dissolving the remains of a gnat that made a worse decision.

The name situation is messy because Pinguicula moranensis is not a single, tidy species in the way a rose or a spider plant is. Botanists refer to it as a species complex, which means it includes multiple closely related forms that look similar, intergrade in the wild, and have been described and re-described over time with overlapping names. Different populations across Mexico show variation in leaf shape, flower color, and seasonal behavior, and growers often lump them together because they behave similarly in cultivation.

For a home buyer, the important part is not the exact Latin label on the pot but the shared care requirements that come from their shared evolutionary background.

This plant belongs to the family Lentibulariaceae, which also includes bladderworts and other carnivorous oddities that decided soil nutrients were optional. Membership in this family means carnivory is not a gimmick but a survival strategy.

In the wild, these butterworts grow in mineral-poor environments such as limestone seep edges and rocky slopes where rainwater constantly washes nutrients away.

Instead of relying on roots to pull nitrogen and phosphorus from soil that has none to give, the leaves took over that job.

The rosette growth habit means the leaves radiate from a central point and stay low and flat, hugging the surface they grow on. Visually, this creates a compact, symmetrical plant that rarely looks messy when grown well.

Functionally, it maximizes surface area for insect capture while keeping the crown, which is the central growing point, close to stable moisture.

Carnivory here is about nutrition, not aggression.

The leaf surface is covered in glandular trichomes, which are tiny hair-like structures that act as both glue traps and digestive factories. Some glands secrete sticky mucilage that traps insects, while others release proteolytic enzymes, meaning enzymes that break proteins into usable amino acids.

These enzymes are highly specific and mild outside their intended context.

They do not burn skin, poison pets, or digest anything larger than an insect because they require the chemical cues of prey to activate fully. That specificity is why the plant can be safely handled and why fears about carnivorous houseplant safety are misplaced.

The roots exist mostly to anchor the plant and absorb water. They are thin, fragile, and largely irrelevant for feeding, which is why rich soil is actively harmful. Evolution pushed this plant toward leaf-based nutrition because the habitats it colonized offered light and water but almost no dissolved minerals.

If you want an authoritative overview of the genus and its classification headaches, the Royal Botanic Gardens, Kew maintains a useful summary of Pinguicula diversity and distribution at https://powo.science.kew.org/.

QUICK CARE SNAPSHOT

Care Factor	Practical Range
Light	Bright indirect, equivalent to a well-lit window without direct midday sun
Temperature	Comfortable room temperatures, roughly what humans tolerate without complaints
Humidity	Normal household levels with some air movement
Soil pH	Acidic to neutral, comparable to rainwater passing over stone
USDA Zone	Outdoors only in zones 9–11 with protection
Watering Trigger	Surface moisture loss without full drying
Water Source	Rainwater, distilled, or reverse osmosis

Those tidy categories hide a lot of real-world decision making.

Bright indirect light means the plant should receive strong illumination without the sun beating directly onto the leaves during the hottest part of the day. Think of the brightness near a window where you can read easily without squinting, but where the sun does not cast sharp, hot shadows at noon.

Putting it in direct midday sun because it is “a carnivorous plant that eats bugs outdoors” is a fast way to cook the glandular surface, which kills the very structures responsible for feeding and leaves permanent scars.

Temperature tolerance is refreshingly reasonable. If the room is comfortable enough that you are not reaching for a sweater or a fan, the plant is fine.

Prolonged exposure to cold drafts or hot appliances is what causes trouble, not seasonal fluctuations within normal household ranges. Avoid placing it against cold glass in winter or on top of electronics that vent heat, because uneven temperature stresses the crown and dries leaves irregularly.

Humidity does not need to be tropical, despite what terrarium photos suggest. Average indoor humidity works as long as there is airflow. High humidity with stagnant air invites mold and bacterial issues on the leaf surface.

This is why sealing it inside a decorative glass container without ventilation often ends badly, even if it looks attractive for a week.

Soil pH is mentioned because mineral content matters more than acidity itself. The plant expects water and substrate similar to rainwater running over rock, which contains very little dissolved fertilizer.

Using regular potting soil because it “drains well” is a mistake. Fertilizers and compost salts accumulate and burn the glands at a microscopic level.

USDA zone information matters only if you plan to keep it outdoors year-round.

Mexican butterworts are not frost-hardy, and brief cold snaps below freezing damage tissue beyond repair. Keeping one outside in a climate colder than zone 9 without protection is a gamble with predictable results.

Watering is triggered by moisture loss at the surface, not by a calendar. Letting it dry completely collapses turgor pressure, which is the internal water pressure that keeps leaves firm and functional. Rehydrating after full collapse is slow and sometimes incomplete.

On the other hand, constant saturation without oxygen causes root and crown rot.

Balance matters.

Water source is the silent killer.

Tap water in many regions contains dissolved minerals that build up invisibly until the plant declines for no obvious reason. Distilled, rain, or reverse osmosis water lacks those minerals and keeps the enzyme systems functional. Using tap water because “it seems fine so far” is how most butterworts die slowly.

WHERE TO PLACE IT IN YOUR HOME

Placement is less about decoration and more about physics. Bright indirect light encourages the development of healthy glandular trichomes, which are responsible for both stickiness and digestion. Without enough light, the plant still grows leaves, but they are thinner, less sticky, and increasingly decorative rather than functional.

Carnivory shuts down not out of spite but because producing enzymes costs energy that the plant cannot afford without adequate photosynthesis.

Direct midday sun is a different problem. Despite eating insects, Mexican butterworts are not built for sustained heat on the leaf surface. The glands dry out, proteins denature, and the leaf tissue burns, leaving pale or brown patches that never recover.

Morning or late afternoon sun filtered through glass can be acceptable, but harsh overhead sun through an unshaded south-facing window is usually too much.

North-facing windows are often too dim. The plant may survive, but survival is not the same as thriving. In low light, leaves lose their tackiness and flatten excessively as the plant stretches for photons.

People often interpret this as a watering issue and respond by drowning the pot, which solves nothing and creates new problems.

Kitchens frequently work better than living rooms for reasons that have nothing to do with décor. They tend to have brighter ambient light, slightly higher humidity from normal use, and more insect traffic, which provides occasional meals without intervention.

Living rooms are often dimmer and drier, optimized for furniture rather than plants.

Terrariums are tempting and often fail.

Without airflow, moisture lingers on leaf surfaces and in the crown, encouraging fungal growth. The plant does not need sealed humidity, and depriving it of air exchange is a recipe for rot. If enclosed display is unavoidable, active ventilation is necessary, otherwise the plant slowly suffocates under perfect-looking conditions.

Dark shelves stop carnivory entirely. Heat mats create uneven drying that damages leaves from below.

Rotating the pot every week or two keeps the rosette symmetrical and prevents one-sided growth toward the light source. Gentle airflow reduces the chance of crown rot by preventing moisture from sitting where leaves meet.

Ignoring airflow because “it’s indoors” is how microbial issues take hold quietly.

SUBSTRATE & ROOT REALITY

Mexican butterworts reject nutrient-rich soil with impressive consistency. In their native habitats, they grow where water is abundant but nutrients are not, such as limestone seeps where rainwater washes minerals away almost as fast as they arrive.

Their roots evolved under those conditions and remain poorly equipped to handle fertilizers, compost, or organic matter designed for typical houseplants.

Peat-based, mineral-free media mimic those conditions by holding moisture without supplying nutrients. When combined with inert materials like perlite or washed sand, the substrate maintains oxygen pockets that roots need to avoid suffocation.

Oxygen diffusion matters because these roots are thin and delicate. In stagnant, waterlogged conditions, they rot quickly, cutting off water uptake and destabilizing the entire plant.

Using fertilized soil kills glands indirectly. Dissolved salts accumulate in the leaf tissue, disrupting the osmotic balance that allows glands to secrete sticky mucilage and enzymes. The leaves may look fine initially, then gradually lose stickiness, turn pale, and stop functioning.

This decline is often misdiagnosed as aging or light stress when the real culprit is the substrate.

Repotting should be infrequent and gentle.

The roots do not appreciate disturbance, and frequent repotting introduces opportunities for mineral contamination and physical damage. When it is necessary, usually because the substrate has compacted or accumulated minerals, the process should involve minimal handling and immediate return to stable conditions.

Signs of substrate mineral buildup include white crusts on the surface, declining leaf stickiness despite good light, and a general look of stress without obvious pests. Flushing with pure water can help temporarily, but long-term correction usually requires fresh substrate. The International Carnivorous Plant Society provides substrate guidelines grounded in cultivation experience at https://www.carnivorousplants.org/.

WATERING LOGIC

Watering Mexican butterworts is about understanding limits. Tray watering works because it allows the plant to absorb moisture from below without saturating the crown. A shallow tray with water that reaches partway up the pot encourages even moisture while preserving air in the upper substrate layers.

Leaving the pot sitting in deep water constantly removes that oxygen and leads to rot.

Seasonal changes matter. Many forms in the Pinguicula moranensis complex produce a tighter, less sticky winter rosette with smaller leaves.

During this phase, water use drops. Continuing summer watering habits into winter keeps the substrate too wet, inviting microbial problems.

Slightly reducing water levels during this period respects the plant’s physiology.

Low-TDS water preserves enzyme function.

Total dissolved solids refer to minerals dissolved in water. High levels interfere with the chemical gradients that allow glands to secrete and reabsorb fluids.

Using pure water keeps those systems intact.

Using tap water because it is convenient introduces an invisible problem that compounds over time.

Drying completely collapses turgor pressure, the internal pressure that keeps leaves firm. Once collapsed, cells may not fully recover, leading to permanently deformed leaves. On the other extreme, soggy crowns deprive tissues of oxygen, allowing bacteria and fungi to colonize.

Leaf texture is a useful signal.

Firm, slightly pliable leaves indicate good hydration.

Limp or glassy leaves indicate trouble.

Misting is unnecessary and often harmful.

It wets the leaf surface without addressing root hydration and encourages mold.

Ice cube watering myths belong in the same category. Cold shock damages roots and does nothing beneficial for moisture control.

Consistent, room-temperature pure water is the goal.

PHYSIOLOGY MADE SIMPLE

The leaf surface hosts different glandular trichomes with distinct jobs.

Adhesive glands secrete the sticky substance that traps insects, while digestive glands release enzymes once prey is secured.

This division of labor makes feeding efficient and prevents unnecessary enzyme loss.

Nitrogen obtained from insects supports chlorophyll stability, which keeps leaves green and functional. Without supplemental nitrogen from prey, the plant can survive on light alone but often grows more slowly and produces less robust leaves.

Heterophylly refers to the production of different leaf forms during different seasons. In Mexican butterworts, this often means broader, sticky summer leaves and tighter, less carnivorous winter leaves.

This is a response to changing light and moisture, not a sign of distress.

Turgor pressure is the internal water pressure that keeps plant cells rigid. It drives subtle leaf movements that help press prey into digestive zones. When water balance is disrupted, that pressure fails, and leaves lose both shape and function.

Roots play a minimal nutritional role. They exist to anchor and hydrate.

Treating them like the feeding organs of a typical houseplant misunderstands the entire system and leads to predictable failure.

COMMON PROBLEMS

Why are the leaves shrinking?

Shrinking leaves usually point to insufficient light or mineral stress. When light levels drop, the plant conserves energy by producing smaller leaves with fewer glands.

Mineral buildup exacerbates this by interfering with cellular water balance. Increasing light gradually and correcting water and substrate quality addresses the cause.

Overwatering in response makes the problem worse by stressing roots.

Why did it stop catching insects?

Loss of stickiness is almost always environmental. Low light reduces gland production. High mineral content disrupts secretion.

Extremely dry air can also desiccate the mucilage.

Spraying sugar water or trying to feed it manually is a bad idea because it attracts mold and overwhelms the leaf surface.

Why are leaves turning pale or transparent?

Pale leaves suggest light imbalance or mineral toxicity.

Transparent patches often follow sunburn or chemical damage.

Moving the plant abruptly into stronger light causes bleaching.

Adjusting light slowly and flushing minerals prevents further damage. Cutting off damaged leaves is fine, but aggressive pruning stresses the crown.

Why is the center rotting?

Crown rot comes from stagnant moisture and poor airflow. Water sitting where leaves meet creates a microbial playground.

Improving airflow, reducing water levels, and removing affected tissue early can save the plant. Sealing it in a humid container guarantees recurrence.

Why does it look different in winter?

Seasonal leaf changes are normal. Smaller, tighter leaves reflect reduced growth, not dormancy in the strict sense. Panicking and changing care dramatically often causes more harm than letting the plant follow its cycle with slight watering adjustments.

PEST & PATHOGENS

Fungus gnats occupy a strange dual role. Adults become meals, while larvae chew roots and spread pathogens. Allowing constant wetness invites them.

Reducing surface moisture and improving airflow keeps populations in check without eliminating a potential food source.

Aphids are more serious. They pierce leaf tissue and disable glandular surfaces, shutting down feeding.

Gentle rinsing with pure water or careful use of insecticidal soap diluted to safe levels can work, but harsh chemicals kill glands along with pests.

Mold appears under stagnant humidity and poor air exchange.

White or gray fuzz on substrate or leaves indicates conditions that favor fungi over plants. Increasing airflow and removing affected material is more effective than spraying fungicides that damage sensitive tissues.

Safe treatments prioritize mechanical removal and environmental correction. Chemical overkill is a common mistake driven by panic. When infestation overwhelms the crown, removal of the plant is sometimes the only way to protect nearby specimens.

The University of California Integrated Pest Management program offers guidance relevant to delicate plants at https://ipm.ucanr.edu/.

Propagation & Pruning

A healthy rosette shows even leaf spacing and subtle surface sheen from active glands.

Propagation with Mexican butterworts is refreshingly low drama, mostly because the plant already expects pieces of itself to go missing in the wild. Leaf pullings work because each healthy leaf contains meristematic tissue, which is a pocket of cells that never quite decided what they want to be when they grow up. Given moisture and light, those cells can reorganize into an entirely new rosette.

The trick is patience, not technique.

A gently detached leaf laid flat on appropriate substrate will often produce tiny plantlets along the base where the leaf meets the surface.

What not to do is shove the leaf vertically into soil like a cutting from a houseplant, because butterwort leaves rot when buried and suffocate when deprived of airflow.

Division is even simpler but timing matters.

Mature plants occasionally produce offsets at the base of the rosette, especially after a strong growing season.

Separating these works best when the plant is actively growing and the crown tissue is firm.

Forcing division during the winter leaf phase, when growth slows and leaves become smaller and less sticky, risks tearing the central meristem.

That damage does not heal cleanly and often results in rot. Seeds exist, technically, but they are slow, unpredictable, and usually reserved for breeders who enjoy waiting months to discover what they accidentally created.

Seeds also introduce genetic variability, which sounds exciting until the resulting plant refuses to behave like the one you liked.

Pruning, in the traditional sense, barely applies.

Dead leaves can be removed once they detach easily, mostly to improve airflow and reduce fungal interest.

Tugging on leaves that resist is a mistake because it injures the crown tissue, which is the growth engine of the plant.

Butterworts do not appreciate cosmetic interference.

Every leaf is a functional organ until it clearly gives up, and intervening early does not make the plant look better or grow faster.

It just creates wounds in a plant that prefers a quiet life.

Diagnostic Comparison Table

Understanding Mexican butterwort care becomes easier when it is placed next to plants people already recognize or mistakenly treat the same way.

The following comparison highlights why familiar instincts often fail.

Feature	Pinguicula moranensis	Saintpaulia ionantha	Drosera capensis
Feeding strategy	Sticky enzymatic leaves digest insects for nutrients	No carnivory, relies entirely on roots	Sticky tentacles actively move to trap prey
Substrate tolerance	Extremely low mineral, airy, nutrient-poor	Light but nutrient-containing potting mix	Low mineral but consistently wet media
Light needs	Bright indirect, strong but cool	Medium indirect, forgiving	Very bright light, tolerates some direct sun
Beginner success	Moderate with correct water	High with basic care	Moderate, fails quickly with poor water

The butterwort looks deceptively like a violet, which is why people try to grow it like one. That instinct leads directly to mineral burn and dead glands because African violets tolerate nutrients that butterworts interpret as poison. Drosera, another carnivorous plant, encourages the opposite mistake.

Sundews enjoy wetter conditions and more intense light, so treating a butterwort the same way often results in a soggy crown and transparent leaves. The butterwort sits between these extremes and punishes overconfidence.

Its feeding strategy is passive, relying on insects blundering onto sticky leaves rather than being actively ensnared.

That means it does not need constant prey or intervention. The substrate must remain low in dissolved solids because the digestive glands shut down when mineral concentrations rise.

Light must be strong enough to support gland production but not so intense that leaf tissue overheats. This balance is why success comes from restraint rather than effort.

If You Just Want This Plant to Survive

Survival, not perfection, requires a minimalist mindset that feels counterintuitive to anyone used to fussing over houseplants.

A stable spot with bright indirect light, a pot filled with appropriate low-mineral substrate, and disciplined water quality will carry the plant further than any feeding schedule or gadget.

The biggest mistake is assuming carnivory requires participation. Dropping bugs onto leaves, spraying fertilizers, or adjusting conditions weekly all introduce stress. The plant evolved to handle inconsistency in prey, not inconsistency in environment.

Stable light matters because gland production responds slowly. Moving the pot every few days to chase sunbeams forces the plant to constantly recalibrate leaf chemistry. That shows up as reduced stickiness and stalled growth.

Water quality discipline matters because minerals accumulate invisibly until the roots and glands shut down.

Using tap water “just this once” is rarely fatal immediately, which encourages repetition until damage becomes obvious and irreversible.

What not to do is trust rainwater collected from roofs or balconies, because it often contains dissolved metals and pollutants that concentrate in small pots.

Restraint also applies to seasonal changes. During winter, many Mexican butterworts produce smaller, less carnivorous leaves.

This is not a cry for help. Increasing water, light, or food during this phase only increases the risk of rot because metabolic demand is lower.

Interference at this stage often kills otherwise healthy plants.

Survival depends on allowing the plant to cycle naturally while keeping its basic needs boringly consistent.

Buyer Expectations & Long-Term Behavior

Growth is moderate, not explosive.

A healthy butterwort fills its pot gradually, producing new leaves from the center while older ones retire quietly.

Over six months, visible change may be subtle, especially if conditions are stable. Over two years, the rosette often becomes denser and more symmetrical, with occasional offsets forming.

Longevity is excellent when care is consistent.

These plants do not burn out after flowering or require renewal, and they tolerate being left alone better than most carnivores.

Seasonal shifts are inevitable. Leaves may become smaller, firmer, and less sticky during cooler, dimmer months.

This does not mean the plant is dying or dormant in the dramatic sense. It is reallocating energy.

Expecting constant visual performance leads people to overcorrect. Relocation shock is another reality. Moving a butterwort from greenhouse conditions into a home often causes temporary leaf loss as humidity, light spectrum, and airflow change.

What not to do is panic-repot or fertilize during this adjustment.

The plant needs time, not solutions.

New Buyer Guide: How to Avoid Bringing Home a Dying Carnivore

Mineral buildup and poor lighting quickly disable gland function in retail environments.

A healthy butterwort announces itself quietly. Leaves should feel slightly tacky without being wet, and the rosette center should be firm when viewed from above. A soft or collapsing crown suggests rot, often hidden beneath intact outer leaves.

Mineral crusts on the soil surface or pot rim are a warning sign that the plant has been watered with mineral-rich water for too long.

That damage does not reverse quickly.

Smell matters. A sour or swampy odor from the pot indicates anaerobic conditions and microbial growth that attack roots first.

Pests are usually visible with a close look.

Aphids cluster near the crown and distort new leaves, while fungus gnats hover but also leave larvae in overly wet soil.

Retail mistreatment patterns include misting foliage, which washes away digestive secretions, and planting in standard potting soil, which slowly poisons the plant.

Avoid specimens displayed in dark corners or sitting in stagnant water with no airflow.

A stressed butterwort can recover, but a structurally compromised one rarely does.

Blooms & Reality Check

Flowers are common and attractive but do not guarantee optimal growing conditions.

Flowering is common and not particularly meaningful as a health indicator. The flower stalk emerges from the rosette center and rises above the leaves, keeping pollinators away from sticky surfaces.

Flowers often resemble small orchids because of similar evolutionary pressures, not shared ancestry. Producing blooms costs energy, and a plant can flower while quietly declining if root or substrate conditions are poor.

What not to do is celebrate flowers as proof that everything is perfect and then ignore other signs.

Conversely, removing flower stalks is optional. Leaving them does not usually harm a healthy plant, but cutting them can conserve energy if conditions are marginal.

Flowers are decorative, not diagnostic.

Is This a Good Plant for You?

Difficulty sits in the middle range.

The biggest failure risk is water quality, followed closely by over-involvement. The ideal environment offers bright indirect light, decent airflow, and an owner willing to resist the urge to tinker.

Anyone expecting rapid growth, dramatic traps, or interactive feeding will be disappointed.

People unwilling to source appropriate water or who prefer heavily fertilized houseplants should avoid carnivorous plants altogether. This plant rewards consistency and punishes improvisation.

FAQ

Is Mexican butterwort easy to care for?

Care is straightforward once the rules are understood, but those rules are inflexible. Most failures come from applying normal houseplant logic to a plant that rejects minerals and fertilizer outright.

Is it safe for pets?

It is safe. The digestive enzymes only function on trapped insects and are ineffective on skin or fur, which lacks the conditions required for enzymatic breakdown.

Does it need to eat bugs?

It benefits from occasional prey, but it does not require manual feeding. In a home with normal insect presence, it usually catches enough on its own.

Can I fertilize it?

Fertilizing the soil is harmful because roots cannot regulate nutrient uptake. Foliar feeding is also risky because it interferes with gland function and can burn leaf tissue.

Why did it change shape in winter?

Seasonal heterophylly causes the plant to produce different leaf types under lower light and cooler temperatures. This conserves energy and reduces rot risk.

Can it grow under grow lights?

Yes, if the light is bright but cool and positioned far enough away to avoid heat. Weak lights produce non-sticky leaves, while hot lights scorch them.

How often should it be repotted?

Repotting is infrequent, often every couple of years, and only when substrate degrades. Frequent repotting damages fine roots and delays recovery.

Why aren’t the leaves sticky anymore?

Loss of stickiness usually indicates insufficient light, mineral buildup, or recent misting. The glands shut down when conditions are unfavorable.

Does it go dormant?

Mexican butterworts do not enter true dormancy but do slow growth seasonally. Treating this slowdown as dormancy and withholding water entirely causes dehydration.

Resources

Botanical clarity improves with reliable sources. The Royal Botanic Gardens, Kew provides taxonomic background and distribution data that explains why the Pinguicula moranensis complex is so variable, available at https://powo.science.kew.org.

The International Carnivorous Plant Society offers cultivation insights grounded in grower experience rather than folklore at https://www.carnivorousplants.org.

University-based explanations of carnivory, including enzyme function and nutrient uptake, are well summarized by the University of California Botanical Garden at https://botanicalgarden.berkeley.edu.

Substrate and water chemistry discussions are handled rigorously by the Carnivorous Plant Nursery California Carnivores at https://www.californiacarnivores.com, which explains why mineral avoidance matters. For physiological background on glandular trichomes and leaf function, the Missouri Botanical Garden provides accessible plant science context at https://www.missouribotanicalgarden.org.