Tropical Gardening: Welcome spring with colorful Rhododendrons, hydrangeas

  • Courtesy of VOLTAIRE MOISE The cool blue of hydrangea flowers complement the warm colors of tropical Vireyas that vary from yellow to orange and rose.

With longer days, many folks are getting chronic Hawaiian spring fever. This means being close to nature with plants.

Hydrangeas are coming on the market with blue, pink or white flowers. They are intermittently available from now to Mothers Day. Hydrangeas generally grow in cool wet areas such as Volcano and Waimea, but can be grown almost anywhere if given enough moisture and shade in sunny, low-elevation locations.


This is also the best time to grow them from cuttings; although, in the uplands you can start cuttings almost anytime.

Also look for members of the Rhododendron family. In Hawaii, these attractive garden shrubs are popular in cool, mauka areas. This spring, the plants are also available as potted houseplants at our local garden shops and nurseries.

If you are looking for some spring color to perk up your home or garden, Azaleas and tropical Vireya Rhododendrons are a natural. They are great gifts for Mother’s Day coming in just a few weeks. In fact, they are perfect for a gift just about anytime, since living gifts are gifts of aloha.

Azaleas and Vireyas are usually found in cool, moist regions. Some are even found on high mountains. Many species of this group are adapted to temperate regions, but some have found Hawaii a good place to live, especially the Vireyas.

Some are terrestrial and some are epiphytic.

Some you will find on the market bloom in reds, whites, pinks, yellows and even mixes of white-pink and white-red. They are relatively slow growing in Hawaii. That is why a gift of an azalea is something special. Once you buy your living spring bouquets, they are easy to care for if you follow a few simple rules.

The plants will take on a healthy look with an occasional leaf washing. This will discourage insect and mite buildup. In general, plants require a thorough soaking at least once a week. In warmer temperatures or air conditioning, plants might require more water. Make sure the pot has sufficient drainage.

Protect the plants from being broiled alive by direct sun and hot or windy areas. In cool mauka areas, they can be placed in sun.

They like their food served at regular intervals. Special acidic azalea fertilizers are available. The best suggestion of feeding is to follow the directions on the plant food container.

Here are some tips on diagnosing plant troubles.

Brown tips or burned margins might mean you applied too much fertilizer, you let the plant roots dry out or you let the plant become wind burned.

Yellowing leaves indicates overwatering, poor drainage or poor soil aeration. Small leaves suggest a tight or heavy soil mixture, lack of fertilizer or not enough moisture.

Weak growth or light green color on otherwise healthy foliage indicates too much light, lack of fertilizer, root rot or poor root systems. Yellowing, wilting or soft growth means too much heat or root injury.

Remember, most require an acidic soil. If you decide to plant them in the garden or repot them, give plants a mix high in peat moss. Make sure you don’t plant them in soils that are high in calcium. Avoid planting in concrete containers, near sidewalks or concrete foundations since these contain calcium and will cause nutrient deficiencies. Also remember, they should not be planted near the ocean or in hot, dry or windy areas.

If you want to learn more about the Rhododendron family visit the Panaewa Rainforest Zoo just a few miles from Hilo. There is a great collection of Vireya or tropical Rhododendrons to view.

We also are fortunate to have a chapter of the American Rhododendron Society here that meets monthly to share information on plant propagation and care.


Because of pandemic restrictions, however, meetings are limited, but you can still network with memebers of the local chapter. For information, contact Sherla Bertelmann at 966-9225 or

This Sunday, April 18, there will be a chapter meeting at president Lucy Moody’s home in Leilani Estates. Call her at 965-9114 for directions. Lucy’s email address is

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