tropicals Archives

Bringing tropical cuttings and seeds to life

If you love plants, coming home from a trip with a bunch of seeds and plants in tow is like adding an extra day to your vacation.

All but a single one of these bags was approved at the USDA checkpoint to travel from Hawaii to the mainland, since the U.S. government is primarily concerned about the risks of transporting pests contained in commercial crops and fruit. As tropical plants washed free of soil, pulp, cotton, leaf spots and bound for a quarantined indoors setting, there’s little risk that any would become invasive threats in Colorado’s snowy climate.

Like an 8 year old back from trick-or-treating with a cache of Halloween candy, you spread your bounty out over the kitchen table and sort through what you got. After making some quick strategic plans, it’s off to the local garden store to buy some extra seed trays and plastic domes to get started.

Out of the dozens of types of plants I got though the USDA inspection in Hawaii, I feel relatively confident I can grow all but few. The philodendron vines and Monstera are notoriously easy to propagate from stem cuttings, even in plain water. I have two types of Crinum asiaticum (spider lily) seeds, which I’ve grown before and know they’re basically foolproof. Croton cuttings are also fairly easy to root in soil or water, although one of my cuttings is looking pretty wilted after shipping and I’m not sure if it will make it.

A batch *Crinum asiaticum*, or spider lily, seeds planted in a simple seed tray in vermiculite and potting mix. These are very easy to sprout—I figure all 6 out of 6 will survive.

An African tulip tree in Kona covered with flowers and big pods full of seeds.

One species I’m less sure about are the Spathodea campanulata seeds, known commonly as the African tulip tree, which reportedly have low germination rates. The pod I found on a tree growing next to a parking lot in Kona contained what looked like thousands of seeds—a dense, loose mass of flat, lightweight seeds, each imbedded in a thin cellophane-like sheet of tissue. Even the slightest breeze scatters the ultra-lightweight seeds into the air, where they flutter around like mosquitos. (This was an annoyance to the group I traveled with, when a swarm sparkly seeds blasted out of the pod on the dash and into the cab when the air conditioner came on.)

The seeds are plentiful and extremely gregarious travelers, but this plant’s reproduction strategy to is to produce its seeds en masse and allow them to spread far, with lower emphasis on each one’s viability. I’m worried there’s a chance the entire batch dried out too much while it was still on the tree and none will sprout.

The seeds of the African tulip tree are extremely lightweight and plentiful. This bag of seeds came from a single, banana-shaped pod. Although the seeds have a relatively low germination rate, it’s easy to see how *Spathodea campanulata* has become such an aggressive invader in tropical forests where it has been introduced outside its native range. These are headed to a seed tray to see if any will sprout, and will remain indoors as houseplants if they do.

I’m also less sure about the single, grape-sized seed pod I found in a refuse pile in the Maka’eo walking path garden at the old Kona airport (an amazing garden to visit if you are ever in the vicinity, by the way). I thought I knew what it was—I initially thought it was a Euphorbia neohumbertii—but now I’m looking that species up and having some doubts my ID was correct. In any case, the three seeds, which fit snugly in the three-chambered pod and have hard casings that resemble pine nuts, seem like they might be temperamental when it comes to watering the right amount. (An aside: these gardens are amazing place to visit if you are interested in looking at a wide range of tropical plants and succulents. But, though the gardens are unguarded, please don’t pluck any attached plant parts or take out any fallen fruit or other useful material. The gardens are maintained by local people, and theft of valuable plants and food crops has been a problem there).

Finally, I have some seeds from an Aloe of some sort that was absolutely covered in open pods, and a sandwich bag of seeds rom a large planting of Stapelia (also known as “carrion flower”) in Kona that was spewing its cottony fluff all over the sidewalk and beyond. The Stapelia pods look remarkably similar to those of milkweeds, as do the seeds themselves, so I looked the genus up and found Stapelia comes from the same subfamily as milkweed, Asclepiadoideae.

A mound of *Stapelia*, or carrion flower, growing at the community garden in the old airport in Kona. It turns out, *Stapelia* is in the same family as milkweed.

(It’s fascinating, the connections you can make when you know a bit about taxonomy. You can walk into a new environment, knowing hardly anything about the plant species there, and quickly identify a bunch of plants with Google by searching your location + the plant family or genus a specimen seems to belong to).

In any case, I have never grown Aloe nor Stapelia from seed, and sometimes these drought-loving plants can be temperamental to water properly in shallow trays. So we’ll see what happens.

I’ve been fascinated by the seeds from a Delonix regia tree, also known as royal ponciana or flame tree. Coming from an enormous dangling pod, which I left in Hawaii to reduce the risk of carrying pathogens, the seeds look like elongated beans. But unlike beans they come in a waterproof, waxy casing that prevents them from swelling even when soaked in pure water. It’s a strategy many plants and trees employ to encourage their seeds to last longer before they sprout, which gives them more of a chance to spread far and wide or emerge at the right times.

Many varieties of Lupine have a similar seed coating, which makes sense because they are also members of the Fabaceae or pea family, and this is something that can make their propagation more complicated. In the case of Lupine, the translucent seed coating is degraded by winter freeze-thaw cycles, fire, or long periods of time in general, helping the plant to get at least some of its seedlings to lie dormant in the seed bank and spring up in optimum conditions in early spring or after a wildfire clears competitors away. But Delonix regia, a tropical species, doesn’t live with cold winters or with recurrent fire (as far as I know). Instead, I wonder if the casing naturally dissolves in the stomach of an animal or bird, and sprouts great distances away in piles of poop.

In any case, I set seven seeds to soak in a tray of water and none of them looked any different after 24 hours. As a test I scoured the corners of two seeds with a piece of sandpaper, and sure enough, they began swelling from the scoured end, stretching and ripping the waxy coat apart until the entire seed had swelled.

Delonix regia (flame tree) seeds soaking in water. The two larger seeds were scoured at one end with sandpaper, allowing the seed to swell with water and break out of the waxy waterproof coating. The rest look exactly like they did before they went into the tray.

I’m also unsure about the viability of the Terminalia catappa, or sea almond seeds, which were easy to find all over the beaches in Hawaii. Supposedly these too are fickle to grow from seed—many of the seeds cores rot out during the long time that passes between the moment they fall and when the right conditions come along to germinate. The interestingly almond-shaped, lightweight, corky seeds evolved to float in sea water and colonize distant beaches, but are hard to pry open and I was unable to cut any open with the tools I had on hand during my trip. I’m excited about the seeds because the attractive, large-leafed trees seem to be a potential substitution for fiddle leaf figs, which are extremely trendy houseplants, but, in my opinion, are not well suited to life indoors. Fiddle leaf figs are just too finnicky, languishing in the low-light conditions in most homes and developing unsightly spots or dropping leaves at the slightest provocation.

Clusia rosea is another candidate I hope to use to fill the role of the fiddle leaf fig, and I got a few tiny seeds along with some cuttings. The seeds are small and come imbedded in a sticky orange goo that helps them attach to mature trees in a wet forest, germinate on a branch, send aerial roots down to the ground and ultimately overwhelm or strangle the unfortunate host tree. The seeds dry out and die easily (I planted six and the rest were dry and dead within a day), but the cuttings seem resilient, staying very plump and green in transport.

Additionally, there are some dry Pandanus tectorius (screwpine) seeds in my cache, a rare Hawaiian native plant that happens to be extensively cultivated, and I was able to collect the dry seeds from the lawn at a resort.

I’m fortunate to be somewhere with a lot of light, and the plants are getting started in a humidity dome to help them root and also give me a chance to discard any that show signs of flies or disease. However, they’ve all been rinsed and soaked, plucked and preened, and have had any spotted or damaged leaves removed. I’m not expecting any problems, and can’t wait to see what some of them turn out like.

A cutting of *Clusia rosea*, or autograph tree. I have no experience with them but I think they will be very easy to root because the cuttings are still plump and green with no wilting even after days in transport.

Growing amaryllises as houseplants that bloom every year

One of my earliest memories of being excited about plants comes from the heirloom amaryllises my grandpa had packed on every windowsill in their house. He kept them outside on a table or bench each summer, bringing them inside before the weather got cold. They bloomed in scattered succession from November to March. The antique bulbs were inherited from his mother—a non-hybrid species variety with salmon, daylily-sized flowers on curved stems that pale in comparison to the treelike poles bearing clusters of dinner-plate blossoms you find for sale in department stores each year leading up to Christmas. The heirloom has its charm, though, and is hard to find now except in rare specialty shops at a high price.

I was so excited about my grandpa’s amaryllises that he gave me one when I was early elementary school age and it was my first experience caring for an indoor plant. I eagerly propagated it into a small collection. In our embarrassment of riches, though, our family took the antique bulbs for granted. Some were tossed intentionally when they developed scale infestations or mealybugs, others were left out by accident past the first frost and transformed into sorrowful piles of soggy slime. Priority went to newer and more varied kinds of houseplants. I started collecting other types of hybrid amaryllises, cross-pollinating them and creating experimental hybrids with their seeds, and found myself short on space. I didn’t take any plants with me when I went off to college, and after my grandpa passed away in 2017, the last of his heirloom amaryllis bulbs froze to death in a cold snap that penetrated so deep it froze and killed the bulbs that had been stored in pots in their garage.

Sometimes, we don’t appreciate things until they’re almost gone. The amaryllis collection gradually dwindled down to a single specimen now siting on the floor next to the sliding glass door at my parents’ house, infected with a mosaic virus that stunts its growth. In healthier form the variety produces a constant supply of offsets, and my grandpa used to save them all and pot them up to form his vast collection of clones.

A note on names: amaryllis is a misnomer

The flowers we all know as amaryllis are technically not amaryllises at all, but hippeastrums. True amaryllises are temperamental plants native to of South Africa, a genus containing only two species, one fairly common—Amaryllis belladonna—and another extremely rare and yet-uncultivated offshoot only recently identified as a separate species. They are best suited for growing outdoors in dry-summer Mediterranean climates, such as coastal California, where they multiply rapidly and are so resilient that they’ve come to litter abandoned farmhouse plots and hug the neglected corners of parking lots. In contrast, these true amaryllises rot in hot humid climates and are very difficult to master indoors.

True amaryllis, Amaryllis beladonna, is a separate genus from which the popular houseplant has taken its common name. Amaryllis is native to South Africa, whereas the commercial Hippeastrums sold as amaryllis are native to South America.

True amaryllises are commonly referred to as naked ladies or surprise lilies. (And as if the naming confusion wasn’t complicated enough, those common names also apply to the separate but visually near-indistinguishable species Lycoris squamigera, which tolerates colder winters and the humid continental weather of the eastern U.S.) But the genus Hippeastrum, with hundreds of species that have been hybridized to countless colorful cultivars, is much more diverse and widely commercialized than Amaryllis. So it gets credit for stealing all the attention, and the common name.

Most people treat their amaryllis/hippeastrum as a throwaway seasonal decoration, like a poinsettia, enjoying it for a week or two of blooms and then tossing it out to buy a new one the following year. But some people are tempted to try to save their plants, and find them difficult. The plants are drought-tolerant and can hibernate for a long time so they’re close to invincible when it comes to keeping them alive in some form, but the problem is that amaryllis/hippeastrums prefer a lot more light than is available to most houseplants. Struggling to achieve reblooms, people have come up with an array of amaryllis care myths that only complicate the task of growing a healthy plant. In truth, amaryllis/hippeastrums are pretty simple and low-maintenance when put in the right spot.

Getting amaryllises to rebloom

Hippeastrum is a tropical genus native to equatorial parts of South America, and as such, it doesn’t experience much seasonal variation. It has the ability to go dormant in drought, but dormancy isn’t necessary for any purpose. The plant will rebloom in winter or spring on a windowsill without intentional forcing, although, if you have any particular concern about the timing, you can force a brief dormancy by withholding water in fall and re-introducing watering six weeks before you want the plant to bloom. Because dormancy takes time away from photosynthesis, and forces the bulb to sacrifice its existing foliage and invest energy into regrowing it later, I prefer not to force dormancy; flowers typically show up at any time January through May in the popular hybrids and that’s fine with me.

Size is everything

With every five to seven leaves, the amaryllis/hippeastrum plant produces an embryonic flower bud that hangs out inside the bulb until the right conditions occur for the inflorescence to develop. The increasing day length just after the winter solstice will set things in motion, although sometimes just moving the plant to a new spot, or other triggers—intentional or idiosyncratic—will set it off. The only thing that really matters in making flowering possible is growing a big, fat healthy bulb with the energy stores necessary to support the enormous blooms. Lacking a sufficient bulb size, the embryonic flowers will eventually self-abort.

Amaryllis bulbs — Large, onion-shaped amaryllis bulbs are likely to be able to bloom when the dormant buds are triggered by changes in light. While the largest and possibly the second largest bulb in this pot will bloom, the multiple of offsets are too small and will need another year or two to grow.

Different cultivars of amaryllis/hippeastrum bear different sized bulbs, from the size of a shallot in dwarf varieties to a hefty grapefruit in the giant ones. Given the vast genetic range in size, an easy way to tell whether your amaryllis bulb is on track to rebloom is the bulb’s shape. If it’s fat and squat like an onion, that means it’s swelling rapidly, and is likely close to the maximum size and will have the strength to bloom. If it’s more slender like a leek or daffodil bulb, it has probably regressed to a juvenile phase and needs more time to build reserves.

The brightest light builds the biggest bulbs

And for this, the biggest challenge most indoor gardeners have with amaryllis bulbs is giving them enough light. They are at their best outdoor plants in warm climates, where they can naturalize in light shade. When grown at northern lattitudes, they perform best in a greenhouse, sunroom, or a south-facing window. Unless your home is uncommonly well-lit, your best bet is putting the plant directly on the windowsill or as close to it as possible since natural light diminishes dramatically even a couple feet from the glass. Or, you can place the plants outside in partially-shaded areas for summer (ideally in areas sheltered from too much wind or foot traffic). But beware: the straplike amaryllis leaves are prone to kinking or breaking, and when moved, the plant likes to let its existing foliage die off and produce new leaves, which uses precious energy. So you’re most likely to get a large, healthy bulb if you find an ideal spot and leave the plant there without moving it at all for at least 6 months at a time.

Water, soil and fertilizing amaryllis bulbs

Amaryllises are relatively forgiving when it comes to water. It’s good to water them thoroughly for a while and then let them dry out periodically, but avoid leaving them so dry that they begin to drop leaves. In bright summer light and in full leaf, one of the larger plants can use more than a quart of water per week, and in the lush vegetative period it’s OK to keep the soil continually moist. Occasionally, it’s good to let the soil surface become dry to the touch to avoid rot.

Most commercial indoor potting blends are OK for amaryllis, but if the soil is too dense or peaty I like to add perlite, or mix standard potting media with succulent mix. The container should be at least 3 times the diameter of a full-sized bulb, and have drainage holes. (Pots without drainage holes are doomed to failure, which is unfortunate when so many amaryllis grow kits come with pots with no drainage—perhaps the growers’ insurance that customers will have to come back for a new purchase next year?)

Amaryllis should be planted with two thirds of the bulb above the soil surface and should not be repotted often; their thick succulent roots are an expensive investment and disturbing them will force them to regrow, reducing the bulb’s size. They’re more likely to rebloom when rootbound and it is OK to combine bulbs in a container or allow bulbs to coexist with their own offsets. If you choose to force dormancy, it is possible to do so by withholding water or moving the plant into darkness without removing the bulb from its pot. If over the years the soil begins to lose volume or lose its ability to hold water, it’s possible to lift the plant and add soil without completely exposing the root system, although plants will be fine if repotting is limited to every 3-5 years.

Finally, amaryllises are a plant that enjoys a regular feeding, with dilute, well-balanced fertilizer, particularly in the fast-growing vegetative period in summer. That’s when you can really capitalize on the long days and bright light and grow a very large bulb. Avoid fertilizing them in the months leading up to blooming season, since nitrogen will stimulate long stems that are more prone to breaking. To avoid excessive accumulation of fertilizer salts, once or twice a year you can set the container in the sink and flush it thoroughly, letting water drain through the bottom of the pot, then try to return it to the same position it was growing in previously so it doesn’t behave as though it has been moved.

Bringing it home

Some amaryllis cultivars are hardier than others—apparent when identical windowsill conditions produce bulbs of vastly different sizes. In my experience, red or orange-flowered varieties tend to be more vigorous and light pink or white plants are more temperamental, often failing to rebloom when others would. But I don’t know if there’s anything substantial behind that pattern or if it’s just a coincidence. Regardless, it’s more than possible to keep a collection of amaryllis plants alive as houseplants indefinitely, for reliable repeat blooms, as long as you have the light and space. It seems like a shame to toss a perfectly healthy bulb that just finished blooming, and often department stores and clearances will put remaining bulbs on a deep clearance sale just after the season ends with Christmas. If you find yourself tempted, give it a try!

Summary

Amaryllises can be easy plants to grow, but need more light than most houseplants to grow large enough to bloom.

Keep amaryllises in a sunroom or south-facing window, as close to the glass as possible, to give them brighter light.

If you decide to put amaryllises outside for the summer, choose a sheltered, lightly-shaded spot. Be sure to bring them back in well before frost.

A dormancy period is not necessary to get amaryllises to rebloom. It may be easier to grow a larger plant if you don’t force them to go dormant, and avoid pruning off leaves while they are still green.

The natural blooming season for amaryllises indoors is late winter or early spring.

The main factor determining whether an amaryllis can bloom is the size of the bulb. A fat, onion-shaped bulb is a good sign that the plant has enough stored energy, while a thin, slender bulb is likely in a juvenile stage.

Amaryllises need a container with drainage holes in the bottom to thrive.

Try to move the plant as little as often so that the plant doesn’t drop its leaves.

Applying a dilute, well-balanced fertilizer in summer is helpful to promote lots of leafy growth that enlarges the bulb.

Water amaryllis bulbs deeply and thoroughly, then let the soil begin to dry out on the surface before watering again. They can survive long periods without water, but will do better with regular water.

How to grow a pineapple plant from a pineapple top

A young pineapple plant started from a pineapple top

Growing a pineapple plant from a pineapple top is a fun and simple gardening project to do with kids, or an easy way to get a free, low-maintenance houseplant that actually looks pretty good in your home.

A pineapple top rooted a few months ago producing a new set of leaves on top.

For an industrious plant-enthusiast there is a litany of ways to turn grocery store produce or kitchen scraps into live plants—sprouting mango and avocado seeds, planting ginger root or replanting the base of your onions. They’ll all get you something, but out of all the possible scavenged garden projects, pineapple plants grown from pineapple tops make for the most decorative and tidy houseplants that look just as nice as a plant you buy from a department store or nursery. They have an attractive symmetrical shape and interesting spiky leaves, they don’t shed or make a mess and they are easy to keep alive on a windowsill, tolerating both overwatering and underwatering without much fuss.

You need:

A pineapple with a nice, green healthy top

A container or flower pot that is at least 6 inches wide (ideally 8 inches), and has drainage holes in the bottom

A tray to go under the container (unless it’s built into the pot itself)

Potting mix

A knife/cutting board

Scissors (optional)

A bright windowsill that gets direct sun—ideally one that faces south

Putting it together

First, cut the pineapple top off of the pineapple as close as you can get to the spot wher where the foliage meets the fruit. Inside the cluster of leaves there is a short, thick, somewhat fibrous stem that can be difficult to cut through, so if you’re with young kids you might want to leave that part to the adults. Make sure to remove all the fruit from your cutting; it just rots and it’s not where the roots emerge.

First: cut the pineapple top off of the fruit and cut off all residues of fruit.

Next, strip off some of the lower leaves to expose at least a half an inch of the bulky stem. At the base of each leaf you may see a tiny bud or node—those are small roots, ready to grow on contact with soil.

Pull off some of the lower leaves to expose at least half an inch of stem. New roots will emerge from the exposed area after the cutting is planted.

You can trim off dead portions of the leaves or leaf tips as desired to make the cutting more attractive; it doesn’t make a huge difference for the plant unless there was so much brown that it was shading out the green leaves, but it will be more enjoyable to grow if it looks healthy.

I like to use scissors to clean up dead sections of leaves at the tips. It’s not crucial, but makes for a more attractive plant.

Fill your container with potting soil up to about 1″ from the top. Dig a small hole in the center for the pineapple top.

Plant the cutting deep enough to cover all
of the exposed stem and the bases of the lowest leaves.

Press the pineapple top into the soil so that the bare stem section is covered and so are the bases of the lowest remaining leaves. It’s OK if some soil gets into the crevices between the leaves. Compress the soil lightly around the plant.

A newly-planted pineapple cutting at the ideal depth.

Water the plant thoroughly, and place it directly onto your bright sunny windowsill. Pineapples need a lot of sun to root!

Be sure to place the plant close to a bright window to
root. An established plant is more tolerant of receiving less light, but cuttings prefer some direct sun.

That’s it!

Caring for the plant

Keep your pineapple cutting’s soil moist by watering it regularly until a some water drains through and collects in the tray. That’s how you know the soil is saturated. It’s OK to leave a little standing water in the tray; it will help keep the soil moist as some of the water is drawn back in. Leaf tips may brown a bit as the plant struggles to grow roots, and you can trim them back with scissors. But the rooting process does not take very long and the plants aren’t temperamental.

Resist the temptation to lift the plant to check for roots; you could break the roots and force the plant to start over. The first sign that roots have formed is that the leaves will suddenly begin growing, especially the young ones in the center of the plant. They’ll soon stand tall above the others. You can safely cut back on water when that happens, and even add a dilute fertilizer every now and then for faster growth.

Collect different types of pineapple plants

Commercially-available pineapples are grown from 5 main classes with several varieties or cultivars in each class. All pineapples of a particular cultivar are clones (propagated by cuttings). Pineapples can’t self-pollinate, and since they are only grown among their own clones they won’t produce seeds since the plant treats pollen from a clone as being from itself.

The varieties of pineapples in grocery stores lead to slightly different-looking pineapple plants; some form a taller and spikier plant, some form a stouter plant, some plants have a glaucus coating that gives them a nice blue tint and some are deep green. Some have serrated or barbed leaves and some are smooth. You can tell the difference by looking at the pineapple top even before you buy it. The plants may have slightly different light and water needs, but for your purposes at home you can treat them pretty much the same.

Will your pineapple houseplant produce fruit?

A note: you probably won’t ever get a pineapple from an indoor plant; in tropical areas they can form fruit in a year, but indoors the plant will tend to reach a certain size and plateau. It can live indefinitely. However, you can eventually force your plant to fruit by covering it in a plastic bag with a ripe banana inside; the ethylene gas released by the banana will trigger a hormone reaction that forces a small pineapple to emerge in a few months. If it fruits, the main portion of the plant will stop growing and 2-4 shoots will emerge from the sides.

A note on starting your pineapple top in water

Don’t. I know people are used to starting cuttings in water and for many plants it’s a very easy way to propagate them, so it’s the default strategy when trying a new plant. You can find dozens of guides online that tell you to root your pineapple top in a dish with water, but there’s really no reason for it. Pineapples are not tolerant of being submerged; they rot easily in water, especially if there’s any fruit left attached to the stem. Meanwhile, they root with a high success rate in soil. So skip the unnecessary step!