How To Take Care of a Rieger Begonia

Rieger begonias are lovely flowering plants that bloom in bright pinks, reds, yellows, oranges, and whites. They grow quickly and make lovely additions to any garden in the late autumn months. Although they’re usually bred to bloom during the winter and they’re sold as disposable flowers, you can grow them year-round for more fall blooms. Here is everything you need to know about caring for Rieger begonias.

Overview of Rieger begonias

According to The Spruce, the botanical name is Begonia x hiemalis. This is an annual plant unless grown in zones 10 or 11 or grown inside. These plants grow to a mature size between 12 to 18 inches tall and wide. They usually bloom in winter, but other bloom times can be encouraged. This plant is native to Central and South Africa and Southern Asia and prefers warm temperatures. The plants are toxic to pets, livestock, and humans and should not be eaten. They are a cross between wax and tuberous begonias with glossy foliage. The plants flower prolifically with small delicate blooms with single and double petals.

How to plant Rieger begonias

Rieger begonias require well-drained soil. A mixture of all-purpose potting soil is recommended. According to My Garden Life (, there are two ways to plant Rieger begonias. You may pot them for indoor use or outdoors into flower beds. When purchased as potted starts, there is little initial maintenance needed other than keeping the soil moist after transplanting.

Rieger begonias as indoor plants

Transplant into a larger pot to allow the roots to spread out. Choose a container that comes with drainage holes and a plate to catch excess water for the best results. Use an all-purpose potting solid that is organic-rich. Apply a commercial balanced liquid fertilizer once a month. Place in a spot that receives partial sun and water to keep the soil moist, but not saturated. Remove faded flowers to encourage more blooms. Rieger begonias can last for several years if properly cared for. You should repot the plants approximately every two years into a slightly larger container. This prevents the plants from becoming root-bound.

Rieger begonias as outdoor bedding plants

Select a spot in the garden that receives at least partial sun. Using a trowel, dig a small hole in the ground that is just bigger than the root ball. Plant the Rieger begonia in the hole, then press soil around the transplant firmly to ensure that is securely the roots. Do not pack the soil too tightly. After transplanting, water the new plants to help settle the soil around the roots.


Rieger begonias do best when grown in moist soil. The frequency of watering requirements depends on the temperature and climate. Don’t overwater the plants, but it’s best to keep the soil moist. Check the moisture content in the soil periodically to assess watering needs. Outdoor plants usually do well when watered once or twice a week, depending on weather conditions. These plants may need more frequent watering in hot and dry conditions. A good rule of thumb for watering is to check the moisture of the soil with your finger. If the top 2 to 4 inches are dry, it is time to water. Also, water the plants if the leaves begin to wilt.

How to fertilize Rieger begonias

According to SF Gate, Rieger begonias do best with a high phosphorous liquid plant food during the blooming periods. The plant should be fed once per month according to the directions on the label. Do not over-fertilize because this can damage the plant. Follower the instructions for the fertilizer product you choose. Stop fertilizing the plant after the blooming period has stopped. At this point you will also need to reduce the water and keep the soil damp, and barely moist.

Pruning/Cutting back Rieger begonias

After begonias have completed the blooming process for the season, they need to be cut back. Prune all of the stems of the plant to a height of 3-inches. Allow the plant to remain nearly dry, but slightly damp for 6 weeks. Mark the dates on your calendar. At the end of 6 weeks, begin the regular watering cycle again to keep the soil moist. Soon you will see new shoots appear at the base of the plant.

Propagating new Rieger begonia plants

Rieger begonia plants are not difficult to propagate. When the mature plant sends out shoots from its base, wait until the new growth reaches a height of 3 inches. Prepare a pot of half sand and half peat moss and moisten the soil. Cut the shoots from the mature plant, and remove the lower leaves. There will need to be at least one node on the new shoot that is covered in the soil. Plant them in the moist soil mixture. Invert a plastic bag over the top of the pot to rise and maintain the humidity level and encourage growth and rooting of the cutting. Make sure that the plastic bag is placed loosely over the pot to allow air to enter inside. When the plants become established you can either use them as indoor potted plants or transfer them outdoors into flower beds.

Final thoughts

Raising Rieger begonia plants isn’t difficult when you know the simple basics of their care. While many consider them a disposable annual, they can be grown all year round both indoors and outdoors in some of the hardier zones. Follow the recommended regimen of care to convert these throw-away flowering plants into attractive houseplants and bedding flowers for a splash of vibrant color with prolific blooms. This is a plant that is easy to propagate so you can repopulate your flower beds from a single mature plant every year. Rieger begonias are ideal for borders of flower beds, for use as potted indoor flowering plants and they also make wonderful gifts for friends and family.

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