Begonia grandis aka Hardy Begonia
Taxonomy
Begonia grandis, or the hardy begonia, is a species of flowering plant in the family Begoniaceae. This herbaceous perennial has alternate, simple leaves on arching stems and produces blooms that are either pink or white which are borne in dangling clusters from late summer through fall in USDA U.S. Hardiness Zone 7. This plant can overwinter as tuberous roots or bulbils in zone 9a in southwestern Japan and is generally considered hardy in zones 6-7. Varieties such as Begonia grandis subsp. evansiana and subsp. evansiana var. alba have the Royal Horticultural Society's Award of Garden Merit. As with many plants in the Begonia family, this hardy begonia has bright green heart-shaped leaves and is a late bloomer, adding color in midsummer to early autumn, and planted in beds with spring bulbs it will appear only after they have faded. Finall, it's important to note that, while Begonia grandis is interesting and popular with gardeners, there are over 2,000 species and taxonomy is complex, so keep them out of reach of children and pets due to oxalic acid.
Common names
Hardy Begonia, Begonia, Yourakusou (Ja), Winter Hardy Begonia, (Ja)How to care for Hardy Begonia
Difficulty
Hardy Begonia presents a moderate level of care, which allows plant enthusiasts with some experience to expand their skills and knowledge.
Water
Hardy Begonia should be watered regularly, allowing the soil to dry out between waterings.
Soil
Hardy Begonia loves a well-draining soil. Perlite and vermiculite help with drainage, while coco coir adds organic matter, so a good potting soil mix will have all three. You can improve store-bought soil by adding some perlite to it.
Lighting
To ensure optimal growth, the Hardy Begonia prefers bright diffused light for 6-8 hours each day. Insufficient light can result in slow growth and leaf drop, so it's important to find a well-lit location for this plant. Place it near a window, within a distance of 1 meter (3 feet), to enhance its potential for thriving.
Dormancy
The Hardy Begonia does not exhibit a standard dormancy pattern. If a substantial slow-down in growth is noticed, double-check that the plant is getting sufficient sunlight and water for optimal growth.
Toxicity
Hardy Begonia is poisonous if ingested. We suggest keeping this plant out of reach if you have children, cats, or dogs in the home.
Humidity
No additional humidity is required for the Hardy Begonia. Plants take in most of their water through their roots, not their leaves, therefore, watering the soil is the most effective way to supply humidity to your plants.
Fertilizer
Repotting the Hardy Begonia is necessary either when it has doubled in size or once every year, whichever happens first. With fresh potting soil replenished annually, the plant will receive all the necessary nutrients, rendering the use of fertilizer unnecessary. Keep in mind that the source of a plant's energy is the sun, not fertilizer.
Growth-pattern
The Hardy Begonia is a clump-forming species, with new growth originating from the soil surrounding the main plant.
Region of origin
Hardy Begonia’s native range is Tropics and Subtropics worldwide.
More info:
Wikipedia
More Species in Begonia Genus
Begonia dracopelta Begonia Dracopelta
Begonia amphioxus Red Butterfly Begonia
Begonia abdullahpieei Begonia Abdullahpieei
Begonia conipila Fuzzy Begonia
Begonia semperflorens-cultorum Bedding Begonia
Begonia pendula Orange Lantern
Begonia chlorosticta Hardy Begonia
Begonia lubbersii Begonia Lubbersii

Begonia gracilis
