Cold protection of tropical container plants

Q: I am long time customer of yours, I live in San Diego California and while the summer and Fall temperatures are warm to mild, the winter temperatures dip to a point where some tropicals die off. We are experimenting with different variations of way to heat and insulate the pots we have the tropicals planted in as a way to keep them alive during the colder winter months. I was wondering if you knew of the ideal soil temperature for these tropical in order to look their best year round. All of the heaters we have installed have thermostats and temperature adjustments so we can now keep the soil anywhere between a range of between 65-75 degrees. Any advise you can provide would be greatly appreciated.

A: This is a very interesting concept you are working with. Indeed, keeping pots/roots warm, may help a lot! We've been experimenting with cold protection for a long time - for the above-ground plant parts. For sure keeping roots protected (even with a thick layer of mulch) will benefit tropical plants during winter. In case with container plants, this may help dramatically.
The guideline is, tropical plants slow down or stop their metabolism at 65F. As long as you can keep soil above that temperature - this should work great. Of course, the higher the better.
Optimum temperature for growing tropical plants in general - 70-85F. Above 90F, metabolism stops too, unless it's a heat tolerant, desert plant.

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Alocasias and Colocasias, commonly known as Elephant Ears, are both remarkable and popular plants that can bring a touch of tropical elegance to any garden. Here's why they are often considered great additions:

1. Striking Foliage: One of the most captivating features of colocasias and alocasias is their large, lush foliage. The leaves can be enormous, resembling the shape of elephant ears, hence the common name. The foliage is usually rich green, but there are also varieties with hues of purple, black, or variegated patterns. These vibrant leaves create a dramatic focal point in any garden setting.

2. Tropical Aesthetic: Colocasias and alocasias have a distinct tropical vibe that can transform your garden into a lush oasis. Their exotic appearance lends itself well to creating a tropical-themed garden or adding a bold accent to other styles of landscaping. Their large, architectural leaves add a sense of drama and create a stunning backdrop for other plants.

3. Versatility: These plants can be grown in various garden settings. They work well in containers, making them suitable for patio gardens or balcony displays. In larger landscapes, colocasias and alocasias can be planted directly in the ground, either as standalone specimens or as part of mixed border plantings. They can also be utilized around water features or in bog gardens since they enjoy moist conditions.

4. Low Maintenance: Once established, colocasias and alocasias are generally low maintenance plants. They thrive in full to partial shade, preferring a consistently moist soil. Regular watering and occasional fertilization will help them grow vigorously. While they are generally hardy, some varieties may require protection during colder months or overwintering in frost-prone regions.

5. Impressive Size: With proper care and favorable growing conditions, colocasias and alocasias can reach impressive sizes. Some varieties can grow several feet tall, creating a stunning vertical element in the garden. Their size and presence make them ideal for adding structure and height to planting arrangements.

6. Unique Varieties: Colocasias and alocasias offer a wide range of cultivars and species, each with its own distinct characteristics. From the classic Colocasia esculenta to the more exotic Alocasia macrorrhizos, there are numerous options to choose from. You can select plants with different leaf shapes, colors, and patterns to suit your taste and garden design.