We will likely get even more rain this summer. It might be time to think about adding plants that can tolerate moist feet. Begonias are a good candidate. Many species will do well in Kona gardens. The Begoniaceae family includes more than 1,000 species and over 10,000 registered hybrids which makes picking a favorite difficult.
All begonias grow well in tropical or sub-tropical climates and many species feature unusual leaf shapes and color patterns as well as an array of flower shapes and colors. These features along with the ease of cultivation and propagation have made begonias popular garden accents as well as delightful houseplants.
Three types of begonias are found in Hawaii: fibrous-rooted, rhizomatous and tuberous. The names refer to their root systems but the plants within the types are not always closely related. Most begonia plants have oval leaves that are spade-like with a pointed tip. Though sizes and colors vary, the shape is distinctive.
Most of the species as well as the hybrids and cultivars found in Hawaiian gardens are the fibrous-rooted types. These begonias range in size from a few inches to several feet tall. The taller ones are often referred to as ‘cane’ begonias because of their segmented stems. The ‘cane’ types have interesting leaf colors and produce lots of colorful flowers almost year-round.
Several cane hybrids have the cultivar names ‘Sunset’ and are popular here in Hawaii. These cane begonias have long stems with swollen joints that resemble the nodes on a bamboo cane. One known as ‘Hawaiian Sunset’ seems very closely related to ‘Maui Sunset’ and ‘Arabian Sunset’. The names refer to the leaf colors which usually include some red or dark orange areas.
‘Hawaiian Sunset’ produces many pendulous orange flowers as well as bronze-colored leaves with serrated margins. The stem is cane-like with evenly spaced nodes. Like other begonias, it prefers filtered light but can take some sun in cooler locations. This begonia grows well in a humid environment with moist soil that drains well.
‘Maui Sunset’ has multi-colored leaves with wild patterns. Its leaves can contain areas of black and dark pink as well as tones of light and dark green. This hybrid originated from crosses between Rex and other begonia species.
‘Arabian Sunset’ is another hybrid. This one was created in 1992 and is classified in a subdivision of ‘cane’ begonias that has leaves with hints of maroon and red. They have a tear drop shape with ruffled edges like angel wings. The bright pink flowers contrast well with the dark foliage, making ‘Arabian Sunset’ a plant that can brighten up any interior or outdoor area.
Perhaps the best-known begonia is the ‘Angel Wing’ or Begonia ‘Lucerna’. It is another cane begonia known for its stiff, sturdy stems and green leaves shaped like folded wings. It is the characteristic wing-shaped leaves that give it its name. It also has lovely flowers in either red or pink.
Most cane begonias require little care. They prefer bright indirect light, but will grow in shaded areas. Overexposure to full sun or overwatering can be detrimental to begonias. Moist soil that drains well is preferred.
Another fibrous-rooted type is the wax begonia or Begonia semperflorens-cultorum. This one is an ideal bedding plant. It provides a low-growing mass of color in a large area but can also serve as a potted plant. Wax begonias have a wide color range including whites, reds, pinks and oranges. As the botanical name implies, wax begonias are always flowering, producing an abundance of small blossoms which continue year-round here in either full sun or partial shade.
‘Begonia x benariensis’ is also a fibrous-rooted type but has no recorded common name. This shrub-like specimen can grow to four feet tall and is often referred to as ‘Big Red’. It produces bright red flowers and attractive bronze leaves year-round. Unlike other begonias, this one can tolerate full sun as long as it receives adequate water. In fact, the flower colors, as well as the leaf color, are enhanced by sun exposure.
‘Big Red’ is known for the lemony flavor of its flowers. They can be used as a salad accent, as well as a tasty and colorful topping for soups and casseroles or simply used as a plate decoration. Like other begonias this cultivar can be easily propagated from cuttings.
Begonia richmondensis is another fibrous-rooted begonia that is readily available here. It is known as a shrub begonia, can grow to 2 or 3 feet tall and produces lovely flowers in shades of pink that are edible but not as flavorful as those of ‘Big Red’.
Begonia hirtella is a weedy begonia here in Hawaii. It has the typical begonia leaf shape and a flower that resembles other begonias, but it has a somewhat invasive growth habit. It grows well from seed and readily reseeds itself, especially in moist areas of a garden. This small begonia can take over a garden if not controlled.
An outstanding species in the rhizomatous type is Begonia rex. The first Rex begonia was found in a dense tropical forest in Assam, India, in 1858 which is the perfect location for this humidity-loving specimen. According to the American Begonia Society (https://www.begonias.org), all types of the rex begonia are descendants of this Indian specimen. Most grow from a thickened stem called a rhizome but their colorful, bold leaves and specific growing requirements distinguish them from other rhizomatous begonias.
Rex is known for its large, distinctive leaves which are usually very colorful and typically have an interesting shape. Some species have two or three outstanding colors in their foliage and some even have metallic appearing leaves accented with green, purple or splashes of red.
Most Rex begonias will grow twelve to fifteen inches tall in the ground or in a container. They grow best in the shade in soil that is uniformly moist but not wet. They prefer growing conditions with high humidity and are heavy feeders especially when young. They make interesting houseplants when given sufficient moisture and indirect light. Though they require a moist environment, overwatering a Rex can kill it.
Tuberous begonias require special care and are not often grown here in Hawaii. New begonia cultivars are always being developed, however, offering a nearly endless variety of growth habits as well as leaf color markings and patterns.
Because begonias come in such a variety of types, sizes and shapes, it is difficult to generalize about them, but some characteristics seem to unite the family. Most could be classified as herbaceous perennials. They lack woody stems and in the tropical climates, where most originated, they will continue to grow and produce new leaves and flowers year-round.
Most varieties grow best in partial shade and moist soil that drains well. Their roots rot easily in overwatered conditions and dry out when inadequately watered. When the water supply is constant, they can be lovely specimens in full sun which enhances the vibrant leaf and flower colors. The taller, cane-type varieties do require occasional pruning to maintain a compact shape, and all begonias will do best in soil that is healthy and fertile. Adding compost or mulch and some additional fertility will keep your plants happy and healthy.
Begonias are easy to propagate. Some can be propagated from root slips but reproduction using cuttings is the preferred method. Take a stem cutting with 2-4 nodes and place it in water or in a moist mix of 50% each of vermiculite and perlite. Dip the base of the cutting in a rooting hormone and secure it in the mix. Though some varieties do set fertile seeds, the seeds from hybrid species will not produce plants identical to the parent.
Begonias are not usually plagued with pests, though a few insects may take a nibble from time to time. Chinese rose beetles, grasshoppers and the occasional slug or snail may appear. Other insects and diseases are rare.
Begonia varieties are widely available. Many varieties of begonia seeds are available online and plants are available at local nurseries. It’s worth a trip to several nurseries to discover their current supply.
If you are seeking edible varieties, be sure to taste the flowers before you buy. Caution is always advised when tasting plant parts. Be sure you have identified an edible plant and be sure the plants have been grown organically and have not been sprayed with any toxic substances.
Enjoy the search for the perfect begonia to add to your landscape, small garden, container garden or collection of house plants. They will likely reward you with years of pleasure.
Gardening Events
Saturdays:
• “Work Day at Amy Greenwell Garden” from 9 a.m. to 12:30 p.m. Meet at the Garden Visitor Center across from the Manago Hotel in Captain Cook. Come with a mask and prepared to practice social distancing. Volunteers can help with garden maintenance and are invited to bring a brown bag lunch. Water and snacks provided. Visit the website www.amygreenwell.garden/get-involved/volunteer-1/ and sign up for the weekly email for more information on work days.
Thursday, July 20:
• “Nutrien Ag Solutions 2023 Educational Seminar” from 8 a.m. to 3:30 p.m. at the Hilo Hawaiian Hotel. $45 fee includes refreshments, lunch and light pupu session at 6 p.m. Register by Monday, July 10. Contact Ken Ogawa at 808-960-3802 or Aaron Pruett at 808-209-6350 or e mail them at ken.ogawa@nutrien.com or aaron.pruett@nutrien.com for more information.
Farmer Direct Markets
(check websites for the latest hours and online markets)
Wednesday:
• “Ho’oulu Farmers Market” 9 a.m. to 2 p.m. at Sheraton Kona Resort &Spa at Keauhou Bay
Saturday:
• “Keauhou Farmers Market” 8 a.m. to noon at Keauhou Shopping Center Information on their online market: keauhoufarmersmarket.com/onlinemarket
• “Kamuela Farmer’s Market” 7:30 a.m. to noon at Pukalani Stables
• “Waimea Town Market” 7:30 a.m. to noon at the Parker School in central Waimea
• “Waimea Homestead Farmers Market” from 7:30 a.m. to noon at the Waimea middle and elementary school playground
Sunday:
• “Pure Kona Green Market” 9 a.m. – 2 p.m. at Amy Greenwell Garden in Captain Cook
• “Hamakua Harvest” 9 a.m. to 2 p.m. at Hwy 19 and Mamane Street in Honoka’a
Plant Advice Lines
Anytime:
konamg@hawaii.edu
Tuesdays &Thursdays: 9 a.m. to noon at UH-CES in Kainaliu – 322-4893 or walk in
Mon., Tues. &Fri: 9 a.m. to noon at UH CES at Komohana in Hilo 981-5199 or himga@hawaii.edu
Diana Duff is a plant adviser, educator and consultant living part time in Kailua-Kona.