Scarlet begonias are red-flowered members of the enormous Begonia genus, which includes well over a thousand species and thousands more cultivated hybrids. The name most often points to Begonia coccinea, a cane-type species from the coastal forests of Brazil whose dangling clusters of bright red flowers earned it the common name “scarlet begonia.” But gardeners and nurseries also use the phrase loosely to describe any begonia variety that produces vivid red or scarlet-red blooms, from wax begonias to tuberous types. Whether you picked one up on impulse at a garden center or received a cutting from a friend, the care basics are forgiving once you understand what these tropical plants actually need.
What Begonia Coccinea Looks Like
Begonia coccinea is a cane begonia, meaning it grows upright stems with visible nodes that look a bit like bamboo. The stems are smooth, often green or lightly flushed with red, and can reach four to five feet tall indoors if given time. Its leaves are the classic “angel wing” shape: elongated, slightly asymmetrical, with a pointed tip and a waxy sheen on the upper surface. The leaf edges sometimes carry a thin red margin, though this depends on light exposure and the specific cultivar. The undersides of the leaves tend to be paler, sometimes tinged pink or burgundy.
The flowers are the showpiece. They appear in pendulous clusters that dangle below the foliage on slender stalks, and each individual bloom is small but packed tightly enough to form a noticeable spray of color. In the straight species, the flowers are a true coral-red to scarlet, though hybrid forms can lean more toward pink or orange-red. Bloom season is generous for a houseplant: with adequate light, Begonia coccinea can flower from late spring through fall, and sometimes year-round in warm climates.
Begonia leaves in general have some interesting structural traits that help them cope with their native forest-floor habitats. Studies of leaf anatomy across multiple Begonia species have found that most rely heavily on spongy tissue inside the leaf rather than the denser palisade tissue you find in sun-loving plants, an adaptation that helps them capture diffuse light beneath a forest canopy. Large surface cells in the upper leaf layer also serve as a water-storage buffer against dry spells.
Other Begonias Sold as “Scarlet”
If you search for scarlet begonias at a nursery, you may come home with something that is not Begonia coccinea at all. Several other begonia types produce red flowers and get marketed under the scarlet label or something close to it.
- Wax begonias: Begonia semperflorens varieties are the compact, mounded plants you see in mass plantings. Many cultivars produce deep red flowers alongside bronze or green foliage, and they are sometimes sold as “scarlet” simply because of the bloom color.
- Tuberous begonias: These produce larger, showier flowers than most other begonia types and come in nearly every warm color, including true scarlet. They grow from a tuber and go dormant in winter, which makes their care cycle different from cane begonias.
- Dragon Wing begonias: A hybrid group with glossy, wing-shaped leaves and cascading red or pink flowers. They are often confused with Begonia coccinea because the leaf shape is similar, but Dragon Wings are more compact and bushier.
Knowing which type you actually have matters for care. Cane begonias like coccinea want to grow tall and leggy and need staking or pruning. Wax begonias stay low and bushy on their own. Tuberous begonias require a dormancy period. If your plant came without a species label, the growth habit is the fastest clue: tall, bamboo-like stems almost certainly mean a cane type.
Light Preferences
Scarlet begonias do best in bright, indirect light. A spot near an east-facing window or a few feet back from a south-facing one works well in most homes. Direct midday sun can scorch the leaves, especially in summer, causing bleached or brown patches. On the other end, too little light produces leggy growth and few flowers. If your Begonia coccinea has been growing tall with wide gaps between leaves and refuses to bloom, it is almost certainly not getting enough light.
Outdoors, filtered shade under a tree canopy or on a covered porch mimics the dappled forest conditions these plants evolved in. Wax begonias tolerate more direct sun than cane types, which is part of why they work in open garden beds.
Temperature and Cold Sensitivity
Most begonias are genuinely tropical and have little tolerance for cold. The comfortable range for scarlet begonias sits roughly between 60°F and 80°F (about 15°C to 27°C). Below 50°F, growth stalls and leaves may drop. A hard frost will kill most begonia species outright. This is why begonias are grown as annuals in colder climates or kept as houseplants that summer outside and come back in before the first freeze.
Researchers have explored ways to improve cold tolerance in begonias through genetic approaches. One study found that introducing a cold-response gene from wheat into wax begonias (Begonia semperflorens) improved their ability to survive chilling stress.1Plant Cell, Tissue and Organ Culture (PCTOC). Heterologous expression of the TaCBF2 gene improves cold resistance in Begonia semperflorens That is still a laboratory finding rather than something you can buy at a nursery, but it hints at the possibility of hardier begonia cultivars in the future. For now, the practical advice is simple: if nighttime temperatures are dipping toward the low 50s, bring your scarlet begonia indoors.
Watering and Humidity
Overwatering kills more begonias than underwatering. Cane begonias like coccinea store some moisture in their thick stems, which gives them a buffer that more delicate plants lack. The standard advice is to let the top inch or so of soil dry out between waterings, then water thoroughly until liquid drains from the bottom of the pot. Sitting in waterlogged soil invites root rot, the single most common cause of begonia death indoors.
Humidity is a more nuanced issue. Because begonias evolved in humid tropical and subtropical forests, they appreciate ambient humidity above about 50%. In dry winter air, leaf edges can turn brown and crispy. A pebble tray, a nearby humidifier, or grouping plants together can help. Misting the leaves directly is a common suggestion that some growers swear by, but it can backfire by encouraging fungal problems on the foliage, especially powdery mildew. If you mist, do it in the morning so leaves dry quickly.
Soil, Containers, and Feeding
Scarlet begonias want a potting mix that holds some moisture but drains freely. A standard peat-based potting mix amended with perlite works well. Straight garden soil is too dense and holds too much water around the roots. Containers with drainage holes are non-negotiable; decorative pots without them are a fast track to root rot unless you use them as outer sleeves with a nursery pot inside.
Feeding during the growing season supports both foliage and flowering. A balanced liquid fertilizer applied every two to four weeks from spring through early fall is a common approach. Research on container-grown begonias in peat-based media has shown that a large fraction of applied nitrogen and phosphorus can leach out through drainage water before the plant ever uses it, while nutrients like calcium, magnesium, and potassium are retained more efficiently.2Wiley Online Library. Leaching losses of nutrients and yield and nutrient uptake by container‐grown begonia as affected by lime and fertiliser applications to a peat medium The practical takeaway is that frequent light feedings tend to work better than occasional heavy doses. A big dump of fertilizer does not stay in the pot long enough for the plant to absorb it all, and the excess that runs out with watering water is wasted. Smaller, more regular applications keep nutrient levels steadier in the root zone.
One detail from that same study is worth noting for anyone mixing their own media: adding lime to peat-based mixes tended to reduce leaching of nitrogen (in ammonium form), phosphorus, calcium, and magnesium, though it slightly increased potassium losses.2Wiley Online Library. Leaching losses of nutrients and yield and nutrient uptake by container‐grown begonia as affected by lime and fertiliser applications to a peat medium Most commercial potting mixes already contain lime to buffer the naturally acidic pH of peat, so this is less of a concern if you are buying bagged mix. If you are blending your own from raw peat, a small addition of dolomite lime helps both pH and nutrient retention.
Pruning and Shaping
Cane begonias grow upward relentlessly, and without occasional pruning, a Begonia coccinea can turn into a tall, bare-stemmed stick with a tuft of leaves at the top. Pruning just above a node encourages the plant to branch below the cut, which creates a fuller, more attractive shape. The best time to prune is in early spring before the main growth flush, though you can trim lightly at any time during the growing season.
The cuttings you remove do not need to go to waste. Begonias propagate readily from stem cuttings placed in water or moist potting mix. A stem section with two or three nodes will typically root within a few weeks in a warm spot with indirect light. Rooting hormone is not strictly necessary for cane begonias but can speed the process. Research on propagation of other begonia types, such as Begonia rex cultivars, has found that whole-leaf cuttings treated with a plant growth regulator at around 400 parts per million produced the best results for root development and survival rate.3Jurnal Ilmiah Pertanian. Impact of cutting types and commercial plant growth regulators on the propagation of red star begonia (Begonia rex-cultorum) That specific concentration applies to a different begonia group and a commercial rooting product, but the general principle holds: some form of rooting aid improves your odds, and leaf or stem cuttings are both viable depending on the species.
Common Problems
Beyond root rot from overwatering, a few issues show up repeatedly with scarlet begonias.
- Powdery mildew: A white, powdery coating on the leaves caused by fungal infection. It thrives when humidity is high but air circulation is poor. Improving airflow around the plant and avoiding wetting the foliage are the first lines of defense. Fungicidal sprays can help in severe cases.
- Mealybugs and spider mites: Both pests are drawn to begonias, especially indoors. Mealybugs appear as cottony white clusters in leaf axils and along stems. Spider mites produce fine webbing on leaf undersides and cause stippled, yellowing leaves. Wiping with rubbing alcohol (for mealybugs) or spraying with insecticidal soap (for mites) usually controls small infestations.
- Leaf drop: Sudden leaf loss is often a response to a change in environment, such as moving the plant from outdoors to indoors, a cold draft, or a drastic shift in watering routine. The plant usually recovers once conditions stabilize.
- Leggy growth: Stems stretching with long gaps between leaves signal insufficient light. Move the plant closer to a window or supplement with a grow light.
Most of these problems are preventable rather than treatable. Getting the light, water, and airflow balance right from the start avoids the majority of begonia headaches.
Are Scarlet Begonias Safe Around Pets and Children?
Begonias are considered mildly toxic. All parts of the plant contain soluble oxalates, with the highest concentration in the underground portions (tubers and roots). If a dog, cat, or small child chews on begonia leaves or stems, the oxalates can cause irritation and burning of the mouth, tongue, and lips, along with drooling, difficulty swallowing, and sometimes vomiting. The taste is unpleasant enough that most animals spit the plant out quickly and do not consume a dangerous amount.
Serious poisoning from begonias is rare. The oxalate crystals cause immediate discomfort that discourages further chewing, and the concentration in leaves and stems is lower than in the tubers. Tuberous begonias pose a slightly higher risk than cane types simply because the tuber itself is more concentrated and might be dug up by a curious pet. If ingestion does happen, rinsing the mouth and offering water or milk to soothe irritation is the usual first step. Veterinary or medical attention is warranted if swelling is severe or if vomiting persists, but fatal outcomes from begonia ingestion are essentially unheard of in household settings.
For households with pets that like to nibble plants, placing the begonia on a high shelf or in a hanging basket is the simplest precaution. Cane begonias actually look striking in elevated positions where their pendant flower clusters can hang freely.
The Grateful Dead Connection
No article about scarlet begonias would be complete without at least acknowledging why the phrase rings a bell for so many people. “Scarlet Begonias” is a Grateful Dead song first released in 1974, and it remains one of the band’s most recognized tracks. The lyrics use the flower as an image rather than a botanical reference, but the song’s enduring popularity is a big reason why “scarlet begonia” turns up in searches far more often than other begonia species names. Sublime later covered the song in 1992, introducing it to a new generation.
The cultural connection has had a small but real effect on plant sales. Nurseries and online sellers sometimes market red-flowered begonias with a nod to the song, and Grateful Dead fans occasionally seek out the plant as a novelty or gift. If you ended up here because of the song rather than a gardening question, the good news is that Begonia coccinea is genuinely easy to grow and makes a solid houseplant even for beginners. It is one of the more forgiving cane begonias, tolerating occasional neglect better than fussier tropical species. And the drooping red flower clusters are undeniably pretty, song or no song.