How To Grow Colocasia (Leucocasia) gigantea
Thailand Giant and Laosy Giant Growing Tips
P. Schmidt @ In Situ, Thailand
Thank-you for purchasing the world’s largest elephant ear—Colocasia (Leucocasia) gigantea strain. Although it has been shipped to you in a 1-qt pot, this amazing aroid has the potential to reach 9’ tall in a single season! To help super-size your Thailand Giant or Laosy Giant, we’d like to pass along some growing tips based on our own experiences.
Colocasia gigantea Pre-planting Tips:
When to plant:
- Colocasia gigantea will not show much growth until things really heat up so we recommend planting it only when the temperatures are consistently in the 80s. We plant ours in our Raleigh, NC garden in May; and for us, late June to September are the rapid growth months.
- Thailand Giant or Laosy Giant is initially very sensitive to overwatering. Do not let it dry out, but do not let it sit in a puddle either—too much water during the pre-planting stage is the number one killer of Colocasia gigantea When our Colocasia gigantea stock starts to dry out, we water them until the soil is saturated and then allow the pot to drain until no water runs out the bottom.
- The pot that we send you will have enough residual fertilizer to sustain it until warm weather stimulates rapid growth.
Colocasia gigantea Planting tips:
- Thailand Giant grows natively in semi-tropical, monsoon forests in Southeast Asia where it receives heavy frequent rains in well-drained soil.
- The Laosy Giant is from Laos and will also benefit from well drained soil.
- Although other species of Colocasia can tolerate wet feet, Colocasia gigantea cannot. A loose, free-draining, compost rich soil topped with about least 2” of organic mulch is essential. In heavy soils, a raised bed may be necessary to allow excess water to drain away. Remember that Thailand Giant may grow as large as 9’ tall and wide, so prepare a planting site that is the appropriate size. Water it in.
Keeping it going:
- Once the Colocasia gigantea becomes established, it wants heavy frequent watering. You can also add compost or other fertilizer at this time. More water = more plant.
Growing Colocasia gigantea in Containers
- When up-potting your Colocasia gigantea, we recommend that you do so incrementally. We send it to you in a 3.5” plastic pot. Initially you can bump it up into a 6” pot and once it takes off, you’ll be able to increase the pot size quickly (eventually to well over 15” dia). Generally, the roots should always fill the majority of the potting mix to help assure the pot does not hold too much water (promotes root rot). Of course, the pot must have drainage holes. The larger the container, the more super-sized your elephant ear can be.
- We grow our Colocasia gigantea plants in a well-draining, high-quality, potting mix. We recommend a potting mix that retains some water but is well aerated—these mixes are usually composed of finely ground pine bark, mixed with some sand, perlite, or vermiculite. Often, generic brands or “moisture control” types seem to stay too wet. Also, we advise against putting rocks in the bottom, since it can promote root rot.
- We use compost here at PDN. The more the better, but only apply it during active growth.
Overwintering Colocasia gigantea
- Colocasia gigantea is a solid zone 8 plant and needs winter protection in colder climates. We grow ours in zone 7b and we take the following steps to protect our plant during the winter:
- We plant it in a spot that stays dry in the winter to prevent winter rot.
- In the late summer or fall we dig up the plant and re-plant it 6” deeper. Colocasias tend to move upward in the soil profile over time. We have to counter this tendency so that the crown does not freeze.
- In the fall, we remove the dead foliage and pile a mound of shredded leaves on top of the bulb for insulation. 6” of leaves is plenty.
- In the late spring, we remove the leaves so that the ground does not stay too moist.
- Your Colocasia gigantea may not emerge from winter dormancy until well into the summer. Please be patient and do not panic. In our Raleigh, NC garden we sometimes have to wait until July before ours emerges.
- North of zone 7b you should over-winter Colocasia gigantea indoors. Since Colocasia Thailand Giant or the Laosy Giant does not form a large rhizome like other Colocasia species you need to dig it up, pot it, and either treat it like a house plant or cut the foliage off and put the pot in a garage or crawlspace. In either case, you should back way off on the water and stop the fertilizer. Keep the temperature at least 45 degrees F. Treat it the same way you would a brand new plant as per the instructions above.
Enjoy your Thailand Giant or Laosy Giant Colocasia! By August, you could be sitting under its lush tropical shade sipping a Mai Tai. Maybe we’ll join you.
Best wishes – The staff at Plant Delights Nursery.