A Siam tulip sharing a garden bed with coleus. (Photo by Fernando Montalvo)

While I’ve mentioned some pretty well known plants in the previous plant guides, I’d like to shine a little attention on a not-so-well-known perennial called a Siam tulip or Curcuma alismatifolia (also known as curcuma ginger, Siamese tulip, and summer tulip).  These small, tulip-like curcumas (hence the name) can give a tropical gardener a chance at some tulip-style landscaping.  The plant is easy to grow and there are very few pests that will give you trouble.  Northern gardeners will have to bring it indoors for winter, but, in other regions, the plant will thrive year-round.  It is a very versatile plant in the landscape, looking just as awesome on its own as it does in a mass planting.  It is definitely worth giving it a try in the summer landscape.

I originally fell in love with this plant back in 2001 when I was using it to accent a small corner in a customer’s garden.  Since then, I used it quite a few more times, but a few very cold seasons put it on the backburner as far as my designs go.  Recently, I decided to give the plant another try and I’m definitely regretting ever letting it sit on the sidelines.  Heck, even some of the originals I planted in 2001 are still visible at my customer’s property.  This guide is geared towards the specific species C. alismatifolia and the advice given here may not work on all Curcuma species plants.

Siam tulips are natives of Southeast Asia, specifically Thailand and Cambodia; although the plant in the picture above is native to some warm greenhouse in a south Florida nursery.  The plants have leathery-leaves that somewhat resemble a tulip’s leaves.  The tulip resembling, but also cone-shaped “flowers” (does that make any sense?  I wrote it and it confuses me!) produce colorful bracts, but the actual flowers are borne below.  The entire inflorescence is very showy and is found in a strong pink or a greenish-white color.  The white colored blooms tend to look faded sooner.  Flowers are slow to emerge in early summer, or late spring for warmer regions.  However, once out, the blooms last a very long time and make excellent cut flowers.

So where do you start to “tulipize” you summer garden?

At the garden center naturally!  The roots (rhizomes actually) of curcuma gingers can be purchased at various online/catalog nurseries, as well as at many garden centers, including places like Wal-Mart (yes, I know… Wal-Mart isn’t exactly gardening heaven).  These rhizomes are easily planted in the ground and your new curcuma will be around in a few weeks.  While this is an easy process, it doesn’t save you that much from getting a full-sized, flowering plant at a garden center/nursery.  Plants generally start becoming available in late spring and are sold until about mid-fall in some regions.  Some plants’ choice varieties are sold as rhizomes, but Siam tulips are not one of these plants.

Selecting your Siamese tulip is even easier than growing them.  Look for healthy leaves with no browning (a little at the tip of the leaf is OK if you’re having a hard time finding healthy plants) and flowers that don’t look as if they’re done for the season.  For the white-flowered Siam tulips, check for inflorescence browning, which can be more common in that variety.  Finally, check the plant for slugs or snails, which are one of the few things that may mess with your curcuma.  Leaves should be a light, almost pastel green and you want to look for the straightest growing plants.

If you’re planning ahead for next year and are looking to get a discount on the cost of these beauties, you may want to try buying Siam tulips at a national retailer after the plants have passed their prime.  You may get a 50% discount and you can then plant the curcuma in your garden.  The plants will come back the following year in all their glory.  Prices of Siam tulips are in the $2.70 – $4.95 range for a single plant here in central Florida (prices will vary by region).

Looking for that special place.

Finding a place to plant your Siamese tulip isn’t all that hard, unless your entire landscape beds are in a strong shade.  While the plants are generally labeled as full sun plants, capable of withstanding most of the day in direct sun, I find that the plants do just as great in filtered sunlight.  Nope, you don’t have to pass your sunlight through a coffee filter, but placing the plants at the very edge of shaded areas or under a palm tree canopy has this effect.  The plant in the picture above is grown with about six hours of direct sunlight every day (unless clouds are around or a really tall guy stands between it and the sun, but you know what I mean).  The plant does grow in the partial shade and on some stronger shades, but blooming performance will be quite bad and possibly not non-existent.  In summary: sun and filtered sun – good, but under a 2,000 year-old oak tree that was last pruned when it was 2 years-old -  bad.

Watering requirements are easy to remember, but it does have its quirks.  The plant likes moist soil during most of the growing season.  That doesn’t mean river’s edge moist, but you shouldn’t let it get bone dry (are bones really that dry?).   Regular watering should suffice.  Since the plants hail from climates that have wet and dry seasons, it is important not to water during the plant’s dormancy season.  Watering may cause the roots to rot.  The plant’s leaves die back during its dormancy period.  As soon as leaves emerge or growing resumes, resume regular watering unless it is raining regularly.

While you may want to crowd Siam tulips as you would regular tulip plants, you need to respect the difference between the two plants and give the Siam tulips some room to breathe between neighbors.  A good spacing would be about 1.5 feet or more apart; although a foot apart is OK if you need to get a more packed-in look and you are not willing to wait for it.  After new “stems” emerge in the second season, the plants may be about 2 feet wide, so plan your spacing for this.

Cold hardiness is where this plant’s weakness lies.  Like other curcumas and the white-haired folks who frequent Florida in December, Siam tulips do not like the cold very much.  Cold tolerance can vary, but you’re pushing this plant’s limit below 30°F.  I should point out that I know gardeners who claim to have made these survive to 10°F lower, but I usually start seeing attrition below 30°. Always protect the rhizomes from the cold by adding a layer of mulch over the planted area (this layer of mulch can be all those leaves that fell from your trees in fall or the fancy bagged stuff at the garden centers).

Like tulips, you don’t really prune curcumas.  About the only time you use those nifty garden-shears on these suckers is after the growing season or in late-winter, when the visible part of the plant has turned brown.  Simply cut that part off and wait for new shoots to emerge in spring.

Fertilization is just as easy.  You can go two ways.  As soon as new shoots start to emerge, place a nice, slow-release fertilizer on the plant (preferably one labeled for tropical plants).  Or, if you like to work twice as hard, use a balanced liquid fertilizer monthly.  I’ve had success either way , although I use the once a year technique on my own curcumas (I should note the soil in which my curcumas are planted is top-notch).

A very short and useless pest control section.

Because Siam tulips get sick less than the last man standing on earth risks getting venereal diseases, your real pests with this plant will probably be people.  The only problem I ever had with this plant was when a formation of giant grasshoppers landed on a customer’s garden over seven years ago.  They ate some of the leaves, but nowhere near as bad as a lot of the other plants.  In fact, it almost looked like they tried the leaves and moved on.  Maybe they didn’t like Thai food?  Slugs and snails can be a problem, but this is also rare.  A readily available slug control product should do the trick.

Otherwise, your Siam tulip’s greatest danger is the cold.  It really is that simple to grow.  So there you have it!  An easy guide to sort of growing tulips were tulips don’t grow or seeing a summer tulip landscape in places where real tulips grow.

I welcome comments and suggestions in the comment section below.  Also, I try to answer all your Siam tulip concerns as quickly as I can.

Other posts in the Gardenipedia Plant Guide Series:

• A Guide to Growing Gerbera Daisies
• A Guide to Growing Hibiscus
• And Another Guide, This Time For Blanket Flowers.