Tropical plants bring a burst of color and joy to interior gardens as well as decks and patios — giant hibiscus blooms, cascading bougainvillea, glossy mandevilla vines, that instantly make any space feel like a getaway. But keeping them thriving year-round in our high‑altitude climate takes a different approach.
The key is simple: treat tropical plants as outdoor summer plants and indoor winter plants. Once you understand their seasonal rhythm, they become some of the most rewarding plants you can grow.
The Colorado Tropical Rhythm
Outdoors May–September Warm days, warm nights, bright morning sun and afternoon shade, consistent moisture, regular feeding.
Indoors Late September–May Brightest light possible, reduced watering, light feeding.
Spring Transition: Moving Tropical Plants Outdoors
As spring arrives, Colorado gardeners look forward to transitioning their plants outdoors. However, the timing of this move is crucial for the plants’ health and success. Bringing tropical plants outside too early, before conditions are reliably warm, can lead to setbacks. Carefully monitoring the weather and waiting until the risk of cold nights has passed ensures that your plants will thrive as they adjust to the outdoor environment. This thoughtful transition helps set the stage for vigorous growth and abundant bloom throughout the growing season.
It's important to wait for warm nights. Hibiscus, Bougainville and other tropical plants should not go outside until nighttime temperatures stay above 50°F. It's also important to acclimate them to their outdoor environment. This process of getting plants ready for the outdoor environment is called hardening off. Hardening off plants gradually exposes them to outdoor light, wind and temperatures. The process is easy, but it takes time. In fact, you should plan a week or so to get your plants ready to transplant into the garden.
On the first day, pick a sheltered, shady spot under a tree or on the patio and leave them there for 3 or 4 hours. Bring them back inside that night. The second day, leave them out for 5 or 6 hours, the third day 6 or 7 hours, including nighttime. On the fourth day, set your plants in a place where they will receive morning sun. Morning sun is not as harsh as afternoon sun. This will help your plants adjust to direct sunlight. By the fifth day, they should be spending most of the night outside, unless nighttime temperatures are very cold. After 6 to 7 days, your plants should be ready for the outdoors. Even then, you'll want to keep an eye on the forecast. The average last day of frost is May 13, but this can vary greatly, year to year. Be prepared to bring your plants back in if the nighttime temperatures fall.
As the days lengthen and temperatures become more moderate, tropical plants enter their period of peak performance. During this time, these plants will flourish if provided with the appropriate environment. For best results, position your tropical plants where they can receive the gentle light of the morning sun and protection from the harsher rays in the afternoon. This combination of light conditions allows tropical plants to thrive, promoting healthy growth and vibrant flowers throughout the season.
Maintain an even soil moisture level. Don’t let them wilt. Feed them every 12 to 14 days, with a blooming fertilizer such as 12-30-20.
Fall: Preparing for the move indoors. This is the most important season for year-round success. As nighttime temperatures start to cool off, it’s important to bring tropical plants indoors. 50°F is a sign it’s time to bring your plants in. Gradually introduce them to their new environment by acclimating them over two or three days.
Select a spot inside where they will receive bright, indirect light, away from drafts and heat vents, and the temperature is between 55° and 70°F.
When brought indoors for fall, tropical plants may drop some of their leaves and flowers, but with the right light, temperature and watering, they can still survive and bloom. Allow the top 1 to 2 inches of soil to dry out between waterings. Help maintain humidity by placing the plant on a tray with rocks and water. This is a good time to prune leggy to encourage bushier growth and make the plant more manageable.
Continue to feed your plants every two weeks with a 4-9-3 fertilizer such as Happy Frog Fruit and Flower.
Following this rhythm will encourage tropical plants to become long‑lived, reliable, and incredibly rewarding plants.
