Begonias are popular ornamental plants, valued for their diverse foliage colors and striking, long-lasting blooms. These plants include thousands of cultivars, exhibiting a vast range of growth habits, from compact bedding types to large, upright specimens. Determining the correct planting distance depends highly on the specific begonia variety being cultivated. Spacing should always consider the plant’s mature size and the desired visual outcome, whether a dense mass of color or distinct individual plants. A single, universal spacing recommendation does not exist for the genus.
Why Proper Spacing Is Essential
Planting begonias at the correct distance directly influences their long-term health and vigor. Adequate spacing promotes air circulation around the foliage and stems. When plants are crowded, trapped moisture creates an ideal environment for fungal pathogens. This restriction in airflow increases the risk of common begonia diseases, such as powdery mildew and Botrytis blight.
Proper spacing also minimizes competition for limited resources in the garden bed. Closely planted begonias must compete for sunlight, soil nutrients, and water. Resource scarcity can lead to stunted growth, fewer flowers, and smaller leaf size. Allowing each plant sufficient room ensures its root system can fully develop and efficiently absorb necessary elements. Spacing also dictates the overall aesthetic, allowing a gardener to choose between an open display of individual plants or a fully merged ground cover.
Spacing for Upright and Tuberous Begonias
Begonia varieties, particularly the large-flowered Tuberhybrida types and the upright, cane-stemmed begonias, demand the widest planting distances. These categories are characterized by a substantial mature size, often reaching 12 to 18 inches in width and height. The recommendation for these large, vertical-growing begonias is to space them approximately 10 to 18 inches apart, measuring from the center of one plant to the center of the next.
Wider spacing within this range is advised for varieties known to produce particularly large blooms or those intended to be grown as show-quality specimens. Ensuring generous distance maximizes the plant’s energy allocation toward producing expansive flowers and robust foliage. For tuberous varieties, wide spacing is important because it helps to keep the soil surface drier and prevents moisture from accumulating around the crown. This drier environment is a significant factor in preventing the premature rot of the fleshy underground tuber, especially in regions with high summer humidity.
The exact distance should correspond to the specific variety’s expected mature width, aiming for the leaf margins to just barely touch at peak growth. For instance, a cultivar expected to spread 14 inches should be planted at least 14 inches away from its neighbor to avoid overcrowding. Planting too closely risks disease and causes the plants to stretch and become leggy as they compete for overhead light. Utilizing the maximum recommended distance provides the best chance for fully developed, structurally sound, and disease-resistant upright plants.
Spacing for Wax and Trailing Begonias
The smaller, densely branching Begonia semperflorens, commonly known as wax begonias, are used for mass planting and tolerate closer spacing than their upright cousins. These varieties are often planted to create a solid, carpet-like effect of color in bedding displays. To achieve this dense coverage, wax begonias should be planted approximately 6 to 8 inches apart, measured center-to-center.
This closer arrangement allows the foliage of adjacent plants to quickly merge, which is the desired aesthetic for uniform garden beds. When using the smallest annual bedding plants, spacing down to 6 inches can be appropriate, provided the bed is well-prepared with rich soil and receives regular watering and fertilization. The smaller overall leaf size and more compact growth habit of the wax begonia naturally make it less susceptible to the negative effects of restricted airflow.
Trailing begonias, such as Begonia boliviensis or B. pendula, are frequently utilized in hanging baskets and containers. In these settings, plants can be situated even closer, often 4 to 6 inches apart, because the restricted root space and controlled potting mix allow for easier management of water and nutrient levels. When planting trailing types in containers, position them near the edge, allowing sufficient space for the stems to cascade downward without becoming tangled. Providing ample room at the container’s perimeter ensures the stems can achieve their full, graceful trailing habit.