Spotted spurge (Euphorbia maculata) is a low-growing summer annual that is commonly considered a weed. Spotted spurge grows in almost any open area. The stems of this species secrete a milky sap that can irritate the skin and is toxic to sheep. Spotted spurge can be controlled by digging up the plant and its roots and mulching the area to prevent regrowth. It is naturally killed by frost.
I. Appearance and Characteristics
Euphorbia maculata, known as spotted spurge, prostrate spurge (not to be confused with Euphorbia prostrata), milk purslane, or spotted sandmat, is a fast-growing annual plant in the family Euphorbiaceae. While it is native to North America, where it is a common garden and lawn weed in the United States, it has become a common introduced species throughout the world, including Europe, Japan, Korea, Australia, and New Zealand.
Euphorbia maculata is typically prostate, with specimens rarely reaching up as high as 30 centimetres (12 in). The stems spread out in a mat along the ground with each stem rarely greater than 45 centimetres (18 in) long. The leaves are oval but rather elongate, up to 3 centimetres (1.2 in) long, and arranged in opposite pairs. The cyathia, bisexual reproductive structures unique to plants in the genus, are very small, with four white petal-like appendages that are sometimes pink.
The leaves are often marked with a reddish spot in the center, a feature that led to the common name of spotted spurge. It is similar to Euphorbia prostrata, but that species has shorter leaves that are more rounded at the tips. It may occasionally be confused with Euphorbia serpens but the very short and rounded leaves of E. serpens in combination with the larger (but still inconspicuous) cyathia should remove any potential for confusion.
It grows in sunny locations and a variety of soils, and functions as a pioneer species in ecological succession. The sap of this plant is a mild skin irritant and can cause a rash in some people. The sap is poisonous and considered carcinogenic.
II. How to Grow and Care
Sunlight
Spotted spurge thrives best in full sun conditions, which means it should receive at least 6 hours of direct sunlight daily to reach its full growth and health potential. While spotted spurge can tolerate some deviation from this, such as partial sun, significant reductions in light may lead to less vigorous growth and reduced vitality. Spotted spurge exhibits remarkable resilience by adjusting its foliage to optimize light absorption under less than ideal conditions. When grown outdoors, spotted spurge should be planted in locations that receive ample sunlight throughout the day, avoiding shaded areas that might hinder its development.
Temperature
Genus Euphorbia is very large and diverse, so its different species can be found in various habitats, but the majority are well-adapted to a temperature range of -29 to 4 ℃. Many spurges, in spite of having succulent leaves, cannot handle long periods without moisture and need to be watered weekly during hot summer days. Some cactus-like species are well adapted to high temperatures and prolonged dry periods, but most species used for landscaping and decorative gardening require more moisture for proper development.
Watering
Spotted spurge is a drought-tolerant plant, naturally adapted to survive in arid regions with minimal water availability. Its water habits are relatively balanced, needing watering every week to maintain its growth and vitality. Being an outdoor plant that thrives under full sun exposure, spotted spurge has a unique ability to conserve water during the hot summer months, making it a perfect choice for gardeners in dry climate zones.
Soil
Spurges aren’t picky when it comes to soil type. They can grow in a variety of soils. Some species of Euphorbia can even thrive in nutrient-poor soils, requiring only that the soil be well drained. If the soil is full of moisture and is prone to water retention, it will most likely cause root rot.
Fertilizing
Spotted spurge doesn’t require large amounts of fertilizer for normal growth and development. In fact, very little fertilizer is required. As mentioned earlier, some species can thrive even in very poor soils, as long as those soils are well drained. Fertilizer should only be applied when the plants start showing nutrient deficiency symptoms on lower leaves. When the lower leaves turn yellow, it is time to add half-strength liquid fertilizer to the soil. That will keep the plant well fed for several months.
Planting Instructions
Dig a hole twice as wide as the plant’s root ball before planting. Then, turn the container with spotted spurge upside down and let the plant slowly fall into your hands. Place the plant upright in the hole and slowly fill in around the roots with loose and fertile potting mixture, adjusting the planting depth until it is just right. Water it once. Do not overwater, as standing water is not good for the plant.
Pruning
In early spring, if there are any damaged stems, they need to be removed to keep the plants healthy and to optimize their nutrient management. It is advised to cut back a certain number of stems after blooming in order to stimulate consistent flowering and growth of new foliage. When cutting a stem, cut at the stem’s base. It is very important to use gloves while handling and pruning spotted spurge, because their tissues contain milky-white latex sap which is poisonous and can irritate the skin.
Propagation
Spotted spurge can be successfully grown from seeds, but the seeds are rarely commercially available because they are difficult to germinate and stay viable only for a short period of time. Spotted spurge is most commonly propagated via cuttings.
It is important to wear gloves while working with spotted spurge cuttings and to clean the pruning shears thoroughly after pruning, so that any unwanted contact with the sap is avoided. Before planting, it is necessary to leave the cuttings to dry for 2-3 days. This will prevent rot from developing and enable proper formation of the callus tissue. It is advised to plant the cuttings in a soilless medium, such as peat moss, because it provides an optimal environment for proper root development.
Cuttings should be misted regularly, and the pots in which they are planted need to be wrapped in either foil or a plastic bag to preserve moisture. The bag or foil needs to be removed for two hours each day to provide sufficient air and to prevent excess moisture in the medium. If this step is skipped, molds and rots can easily develop and damage the health of the young, sensitive cuttings. When the cuttings develop a root system, they are ready to be transplanted into soil.
Transplanting
Spotted spurge thrives when transplanted in the congenial warmth of late spring, known as /’S1/’, due to its affinity for mild weather. Ideal locations include sunny areas with well-drained soil. Be sure to gently loosen the plant’s roots before transplanting to aid in establishment.
III. Harvesting and Storage
Some species of Euphorbia can be cut for fresh flowers or foliage, such as snow-on-the-mountain (Euphorbia marginata), Euphorbia fulgens and Euphorbiaformosana. When harvesting cuttings, remember to wear gloves, as the sap can be irritating to the skin. It can be cut from the base of the stem. Soak the end of the cutting in hot water for 10 seconds to stop the milky sap from oozing. The vase life for the cutting will be about 5-7 days, and some flower food can extend its life.
When the fruits of Euphorbia plants are ripe, they burst and scatter the seeds over a large surface area. In order to harvest all the seeds, the individual fruits or the entire plant must be wrapped in in nylon, gauze, or similar material before the ripe fruit bursts and releases the seeds.
