Euphorbia, commonly known as spurge, is a diverse genus of flowering plants, ranging from small annuals to large trees and succulents. Some Euphorbia plants exhibit unique characteristics due to a “plant sport,” a spontaneous genetic mutation causing a distinct physical change in part of the plant. These natural variations create visually striking and horticulturally significant new forms.
Understanding Plant Sports in Spurge
A plant sport originates from a spontaneous genetic mutation within the plant’s meristematic tissue, such as shoot tips or buds. This mutation causes a specific branch or section to display characteristics different from the parent plant, including variations in leaf shape, color, variegation patterns, or growth habit.
These mutations are horticulturally significant as they are the origin of many new plant cultivars. When a desirable mutation is observed, it can be isolated and propagated to create a new, distinct variety. The stability of these mutations varies; some sports reliably maintain their new traits, while others may revert to the original form.
Characteristics and Varieties of Spurge Sports
Plant sports in Euphorbia can manifest in several visually distinct ways. One common manifestation is altered leaf color, appearing as variegation or new colorations like reds or purples. These changes are due to variations in pigment production within mutated cells.
Beyond color, spurge sports can exhibit modified growth forms. Dwarfism results in a significantly smaller plant than the parent, maintaining similar proportions. Cresting, or fasciation, is a characteristic where the growing tip flattens and widens, leading to a fan-like or convoluted growth pattern in stems and branches.
Examples include Euphorbia trigona ‘Rubra’, with reddish stems and leaves distinct from the typical green form. Another example is Euphorbia lactea ‘Cristata’, the “Coral Cactus,” showcasing a dramatically crested, wavy form diverging from its parent’s straight growth. These varieties highlight the diverse visual appeal of Euphorbia plant sports.
Cultivating and Maintaining Spurge Sports
Caring for spurge sports involves understanding general Euphorbia requirements and their unique needs. Most Euphorbia species, including sports, thrive in bright light, preferring several hours of direct sunlight daily to maintain vibrant coloration and compact growth. Adequate light prevents etiolation, stretching and pale growth.
Proper watering is crucial, as Euphorbia plants are sensitive to overwatering, leading to root rot. Allow the soil to dry out completely between waterings, especially during cooler months or dormancy. A well-draining soil mix, like a cactus or succulent blend with perlite or pumice, ensures aeration and prevents waterlogging. Maintaining temperatures between 65-85°F (18-29°C) during the growing season supports development.
Propagating spurge sports requires specific methods to pass on unique traits. For variegated or color sports, stem cuttings are effective, as the mutation is present throughout the tissue. Crested forms often require grafting onto a healthy non-crested Euphorbia rootstock for vigorous growth and stability. Managing reversion, where a sport reverts to the parent form, involves promptly pruning off any branches displaying original characteristics.
Troubleshooting Common Issues with Spurge Sports
A common issue with spurge sports is the loss of distinctive traits, like variegation fading or a crested form reverting to normal growth. This reversion occurs when non-mutated cells outgrow mutated ones. To address this, regularly inspect your plant and immediately prune any branches showing signs of reverting to the parent’s original appearance. Removing these sections directs the plant’s energy toward maintaining the desired sport characteristics.
General Euphorbia issues, especially watering problems, also affect sports. Overwatering often leads to soft, mushy stems or root rot, indicated by a foul soil odor and wilting. Conversely, underwatering results in shriveled or crispy leaves and stems, signaling a need for consistent hydration. Adjusting watering frequency based on environmental conditions and soil moisture is important.
Pest infestations, such as mealybugs and spider mites, can compromise spurge sport health. Mealybugs appear as small, cottony masses on stems and leaf axils, while spider mites cause fine webbing and stippling on leaves. Treating these pests with insecticidal soap or neem oil helps control populations. Nutrient deficiencies, less common in well-cared-for plants, can manifest as yellowing leaves or stunted growth, remedied by a balanced, diluted succulent fertilizer during the growing season.