Begonias are popular ornamental plants, celebrated for their vibrant, often continuous blooms and diverse foliage. These tropical and subtropical plants are fixtures in shaded garden beds and sunny containers. Determining the correct planting distance is paramount to ensure these plants reach their full potential. Proper spacing directly influences plant health and the overall success of the display.
The Necessity of Strategic Spacing
The distance between begonia plants is a preventative measure against common horticultural problems, not just an aesthetic choice. Begonias with dense foliage are highly susceptible to fungal diseases like powdery mildew and botrytis blight. These pathogens thrive when moisture is trapped on the leaf surface and airflow is stagnant.
Strategic spacing provides the necessary air circulation to dry foliage quickly, significantly reducing the risk of fungal infection. Overcrowding also forces plants to compete for finite resources like light, water, and soil nutrients. When competition is too high, plants exhibit stunted growth and produce fewer flowers. Providing adequate room ensures each plant receives the resources needed to support its canopy and root system.
Specific Spacing Requirements Based on Begonia Variety
The correct planting distance depends entirely on the begonia’s root structure and its mature size potential, which vary significantly across the genus. Gardeners typically group begonias into three main types based on these characteristics. Using the appropriate measurement for each type ensures a full, healthy display.
Fibrous/Wax Begonias (Bedding Plants)
Fibrous-rooted begonias, commonly known as wax begonias, are small, compact plants used for mass bedding and edging. Their mature spread is modest, typically ranging from 6 to 12 inches wide. Planting them between 8 and 10 inches apart is recommended to prioritize good air circulation.
Planting 6 inches apart creates an immediate, dense carpet of color often desired in commercial landscaping. However, this tighter density requires increased monitoring for disease and may necessitate more aggressive pruning to maintain airflow. The final spacing should allow the edges of the mature plants to just barely touch.
Tuberous Begonias
Tuberous begonias, including upright and pendulous varieties, require generous spacing due to their larger, bushier growth habit. They produce dense foliage and large blooms, making air movement around the canopy a high priority. In the garden, the recommended distance between plants is typically 8 to 12 inches.
For vigorous varieties, such as the large-flowered ‘Non-Stop’ types, 12 to 18 inches of separation may be necessary to accommodate their substantial spread. This wider spacing prevents the dense foliage from becoming a humidity trap, which commonly causes stem rot and powdery mildew. Increased separation also ensures structural support and minimizes stem breakage.
Rhizomatous Begonias
Rhizomatous begonias are primarily grown for their striking, ornamental foliage. They grow from a thickened stem that creeps along or just below the soil surface, forming colonies over time. Their spacing is determined more by horizontal spread than height, so a minimum planting distance of 12 inches is advised.
The mature size of rhizomatous types ranges from miniature to large, meaning ultimate spacing can extend up to 3 feet depending on the cultivar. A closer spacing of 12 to 18 inches results in faster, more complete ground cover. Wider spacing allows individual plant shapes to be appreciated.
Planting Begonias in Containers and Mass Displays
Spacing rules are intentionally adjusted when begonias are planted in containers or used for high-impact mass displays. In pots, hanging baskets, and window boxes, the goal shifts from long-term health to immediate visual saturation. Begonias can be planted considerably closer together in these confined environments to achieve a fuller look right away.
Tuberous begonias, for example, can be planted 4 to 5 inches apart in a container, significantly tighter than garden recommendations. A common guideline is placing three to four plants in a 16-inch diameter container to create a lush, overflowing display. This higher density is sustainable because container growing allows for superior control over the growing medium.
To compensate for reduced air circulation and increased root competition, the planting medium must be managed carefully. Using a light, well-draining potting mix, often amended with materials like perlite, is essential to prevent root rot in crowded conditions. Tighter container planting also requires more frequent attention, including increased watering and a stricter liquid fertilization schedule, as plants rapidly deplete the limited soil volume of nutrients and moisture.