Begonias are popular ornamental plants, cherished for their vibrant flowers and diverse foliage, making them a favored addition to many outdoor spaces. Providing the correct light exposure is crucial for their health and successful growth. This guide details the specific light requirements for outdoor begonias.
Understanding Begonia Light Needs Outdoors
Most common outdoor begonia varieties thrive in conditions mimicking their natural habitat: bright, indirect light. This means a location with ample illumination but no direct, harsh sun exposure. Outdoors, this translates to planting them under tree canopies for dappled sunlight, or on a patio or porch with overhead protection. A north-facing exposure also provides suitable conditions, offering bright light without intense direct sun.
The timing of direct sunlight is important. Gentle morning sun is well-tolerated and can even be beneficial for begonias, aiding photosynthesis without causing damage. However, intense afternoon sun is detrimental, leading to scorched foliage and overall plant stress. While some wax begonias (_Begonia semperflorens_) tolerate more direct sun, especially in cooler climates, filtered or indirect light is best for most outdoor varieties to protect their delicate leaves and vibrant blooms. Begonias are often called “understory plants” because in their native tropical regions, they naturally grow beneath taller plants, receiving filtered light.
Assessing Light in Your Outdoor Space
Assessing light levels in your outdoor planting areas can be done by observing the path of the sun across your garden or patio throughout the day. Note how long different areas receive direct sunlight and its intensity. Repeating this observation over a few days or even weeks can provide a clear understanding of light patterns.
Light conditions are categorized by direct sunlight duration:
Full sun: Six or more hours of direct sunlight daily, often including intense afternoon sun.
Partial sun/shade: Three to six hours of direct sun, with partial shade meaning protection from harsh midday or afternoon rays.
Full shade: Less than three hours of direct sunlight, with filtered or dappled light throughout the day.
While a light meter provides precise measurements, a simple method is to hold your hand a foot above the planting spot and observe the shadow intensity. A clear, defined shadow suggests intense light, while a softer shadow indicates more indirect conditions.
Signs of Improper Light
Begonias communicate their light preferences through various visual cues, making it possible to diagnose issues related to incorrect light exposure. Too much direct sunlight causes distress, with symptoms including scorched or burnt patches on the foliage, crispy leaf edges, and fading leaf color. The plant’s growth appears stunted, and it wilts even if the soil moisture is adequate, indicating stress from excessive light intensity.
Conversely, insufficient light also triggers noticeable symptoms in begonias. Plants starved for light often exhibit leggy or stretched stems as they elongate in an attempt to reach a brighter light source. The foliage may become sparse, and leaves might appear smaller or paler than usual, lacking their typical vibrant color.
A significant indicator of too little light is a reduced number of flowers or a complete lack of blooming, with any blossoms that do appear often being smaller and less vibrant. Acting promptly upon noticing these signs is important to prevent prolonged stress and ensure the plant’s recovery.
Adjusting Outdoor Light Conditions
Once light issues are identified, several strategies can optimize conditions for outdoor begonias. For container-grown begonias, the simplest solution is to relocate them to a spot with bright, indirect light or morning sun and afternoon shade. If direct planting prevents relocation, provide artificial shade using shade cloth, which filters sunlight, or by strategically placing umbrellas over the plants during the hottest parts of the day.
Integrating begonias into existing landscape features can also modify light. Planting them under taller trees or shrubs creates a natural dappled shade environment, mimicking their native understory habitat. Conversely, if an area is too shaded, selective pruning of nearby vegetation can increase the amount of filtered light reaching the begonias. When making adjustments, do so gradually, allowing the plant to acclimate and minimize shock.