Oxydendrum arboreum — an easy houseplant, prefers full sun light
SPECIMEN · FROM THE LIBRARY
Oxydendrum arboreum

Oxydendrum Arboreum

Updated · 356 observations
Photo · (c) teamtigerlily, some rights reserved (CC BY-NC) COURTESY INATURALIST
ON THIS PLANT

Oxydendrum arboreum, commonly known as sourwood or sorrel tree, is a deciduous tree native to the eastern United States. Typically growing to a height of 20-30 feet, it has a narrow, pyramidal shape. The leaves are alternate, simple, elliptical in shape, and have serrated edges. During the summer months, the tree produces clusters of small white flowers that hang down from the branches like bells. These flowers are highly attractive to bees and have a distinctive sour taste when eaten.

Sourwood trees prefer acidic soils and can be found growing in forests or along streams within their native range. They are often used as ornamental trees due to their attractive foliage, unique flowers, and striking fall coloration, which ranges from yellow-orange to deep red.

In addition to their ornamental value, Oxydendrum arboreum has been used for medicinal purposes by Native American tribes for centuries. The bark was traditionally used as an analgesic for toothaches, while tea made from the leaves was believed to have anti-inflammatory properties.

Overall, Oxydendrum arboreum is an interesting plant with both aesthetic appeal and potential medicinal benefits, making it worth considering for cultivation in gardens or natural areas alike.

A note from PlantMom

Sourwood is fairly disease-resistant and is usually not susceptible to disease. In terms of care, this plant is fairly low-maintenance. When grown outdoors it needs little watering, and larger plants typically do not require pruning. Smaller plants, however, should be pruned after they have finished blooming. Sourwoodt is suitable for anyone with outdoor space, such as a garden or deck, and does not demand extensive experience in plant care.

— PlantMom
CARE GUIDE

How to keep Oxydendrum Arboreum.

Light

The sourwood tree thrives in full-day sun but can also tolerate partially sunlit conditions. Light levels affect its growth: abundant sunlight enhances blooms and foliage, yet excessive exposure can scorch leaves, while too little light may lead to fewer flowers.

Water

The common sourwood flourishes in humid woodlands and requires moderate moisture levels. It should be watered every 1-2 weeks, allowing the soil to dry slightly between waterings. Being a deciduous tree, its water needs change with the seasons. In the fall, as it loses its leaves, its overall water consumption decreases.

Temperature

Sourwood prefers temperatures between 41 and 95℉ (5 and 35 ℃) and grows best in a temperate environment. In winter it can tolerate temperatures as low as -20℉ (-29 ℃) but may need protection from extreme cold.

Fertilizer

Fertilize your Sourwood in early spring to encourage healthy growth. Regular feeding boosts its overall health, leading to vigorous development, increased tolerance of challenging conditions, and enhanced resistance to pests and diseases. Keep to a set fertilization schedule for your Sourwood to maintain foliage that is vibrant, richly colored, and lush.

Pruning

The common sourwood is known for its fragrant white flowers and vibrant fall foliage. To keep it healthy and looking its best, prune the tree in early spring. This will help remove any dead or crossing branches, which in turn improves air circulation and light penetration. Additionally, remove any suckers to maintain the tree's structure and control its height, making it more manageable in garden settings.

CHARACTERISTICS

Botanical profile.

Plant Type
Tree, Shrub
Life Cycle
Perennial
Genus
Oxydendrum
Family
Ericaceae
Hardiness Zone
5-9
Mature Height
6.1 m to 9.14 m
Mature Spread
3.05 m to 4.57 m
Leaf Color
Green, Red, Yellow, Purple
Leaf Type
Deciduous
Flower Color
White
Flower Size
2.54 cm
Bloom Time
Mid summer
Planting Time
Spring, Autumn
Harvest Time
Mid summer, Late summer
Native Area
Eastern and southern United States
ALSO KNOWN AS

Other names.

en Sourwood en Sorreltree en ᏅᏙᏇᏯ en Lily-of-the-valley tree en Common sourwood
FREQUENTLY ASKED

Reader questions.

How should I water my Common sourwood tree?

To ensure excellent root development, place a garden hose at the base of the plant. Avoid spraying water directly on the leaves, as this could lead to more watering needs if the plant is exposed to direct sunlight outdoors. To moisten the roots, consider using bubblers or soaker hoses. When adding or removing plants, use soaker hoses that cover the entire garden or bed to encourage deep root growth. After watering, make sure to drain any excess water and allow the soil to dry before watering again. To prevent diseases, water at ground level rather than spraying the leaves. On sunny days, it may be beneficial to spray water on the entire bush. Whether the plant is in a pot or in the ground, keep in mind that Common sourwood prefers deep watering instead of light sprinkling.

Why should I put fertilizer on my Common sourwood tree?

Regardless of the type of Common sourwood you own, regular fertilization is key to promoting overall plant health. Providing the proper nutrients will result in stronger growth and increased resilience to challenging growing conditions, as well as better ability to combat diseases and pests. The foliage of your Common sourwood is particularly appealing, so it is important to maintain its integrity. This can be achieved by implementing a consistent fertilization schedule tailored to your specific Common sourwood. By doing so, you will encourage the development of vibrant, lush leaves with a deep color.

What are the sunlight requirements for common sourwood trees?

Common sourwood trees thrive best when exposed to full-day sun but can also tolerate partially sunlit environments. To flourish, these trees need more than 6 hours of sunlight daily for full sun conditions, or about 3-6 hours for partial sun conditions. The amount of sunlight they receive directly influences their growth, bloom, and foliage quality. However, it's important to be cautious of extreme sunlight exposure, as it may lead to leaf scorch, while insufficient light can reduce flowering. Observing how sunlight moves through your garden to find spots that provide a perfect balance of light and shade is essential for ensuring the plants' happiness.

What are the ideal growing temperatures for Common Sourwood?

Common Sourwood prefers temperatures ranging between 41 to 95°F (5 to 35°C) and thrives best in a temperate environment. It exhibits strong cold resistance and can tolerate temperatures as low as -20°F (-29°C) during winter without requiring specific frost protection measures. However, to safeguard against extreme cold, especially if temperatures are expected to drop below -25°C, it is advisable to wrap the trunk and branches with insulating materials such as non-woven fabric or cloth. Additionally, ensuring the soil is moist before the first freeze in autumn helps protect the plant against drought and water scarcity during the colder months.

What do I do if I give Common sourwood tree too much water or too little water?

Overwatering can cause yellowing, wilting, and dropping of leaves in a Common sourwood plant. The plant may also look dull and have mushy stems. Adjusting the watering schedule can help when these signs are present. On the other hand, wilting can also indicate under watering, which can cause crispy, dry leaves. Check the soil for dryness and give the plant a thorough watering if needed. However, even with enough water, the Common sourwood may still have dry and yellow leaves for a few days due to root damage. Once the plant returns to normal, the yellowing will stop. When keeping the Common sourwood indoors, check the moisture levels in the pot and avoid overwatering. Look out for black spots, and if they are present, let the soil dry out for a few days before watering again. Overwatering can lead to root rot, so if you notice discolored and slimy roots, consider transferring the plant to a different pot. Always prevent root rot by avoiding excessively soggy soil. When planting the Common sourwood outdoors, ensure the soil is adequately watered. If the soil feels too dry, it may indicate underwatering, and the plant will benefit from a sufficient amount of water.

When should I fertilize my Common sourwood tree for the best results?

To keep your Common sourwood healthy, it's best to fertilize it in late winter or early spring. This will provide the necessary nutrients for growth once the weather warms up. In warm climate regions, it's also recommended to give another round of fertilizer in early fall. This helps the tree gather nutrients for the upcoming growing season, and makes it more resilient to winter cold. By fertilizing early, you ensure that new branches have time to grow and withstand the cold.

How does artificial lighting support plant growth indoors?

For indoor plants, especially during winter or in less sunny locations where natural sunlight is inadequate, artificial lighting can be crucial for optimal growth. LED lights are a popular and efficient choice as they can be customized to the specific light wavelengths needed by plants. Depending on their sun exposure needs, full sun plants require 30-50W/sq ft of artificial light, partial sun plants 20-30W/sq ft, and full shade plants 10-20W/sq ft. The light source should be placed 12-36 inches above the plant to mimic natural sunlight conditions, and most plants will need 8-12 hours of artificial light per day to mimic the length of natural daylight hours.

How does low temperature affect Common Sourwood and what are the solutions?

Common Sourwood is notably cold-tolerant, thriving best when temperatures are maintained above 5°C and requiring protection when they dip below -20°C. While the plant typically withstands winter well, temperatures falling below -25°C can lead to potential damage evident in the spring, including brittle and dry branches with no new shoots appearing. To address this, the recommended solution is to prune any dead branches in the spring, which failed to produce new leaves, thereby promoting healthier growth.

How often should I give water to my Common sourwood tree?

The Common sourwood plant prefers deep and infrequent watering, especially if it is planted in pots. Potted plants have limited water storage and the soil tends to dry out faster, so it's important to water them every 3 to 5 days, especially in cold regions. Watering should be done early in the morning when the soil is dry, both indoors and outdoors. You can check the moisture level by feeling the top 2-3 inches of soil, and if it's dry, it's time to water the plant thoroughly. In hot weather, check the moisture daily as the heat can quickly dry out the potting soil. If you have a garden, you'll also need to irrigate the soil. In hot climates, watering once a week is usually sufficient. Only water when you notice the top 2-3 inches of soil becoming too dry, and be mindful of rainwater to avoid over-watering and root rot. Common sourwood plants typically grow during spring and fall, and adding a layer of mulch about 3 to 4 inches deep can help conserve water when they are planted outdoors. The watering frequency depends on the type of soil- sandy soil drains faster and requires more frequent watering, while clay soil retains moisture and needs less frequent watering to prevent root rot. It can be helpful to mark the watering dates on a calendar and pay attention to the condition of the leaves; drooping leaves may indicate that watering is needed.

When is it not a good idea to fertilize my Common sourwood?

There are certain times of the year when you should avoid fertilizing your Common sourwood plant. The first is during the winter months when the plant is dormant and does not require any feeding. It is also not recommended to fertilize the plant during late spring and summer when the weather is hotter and drier. These conditions can have a negative impact on the plant's response to fertilization. To prevent any issues, it is best to stick to a fertilization schedule that involves feeding only in early spring and early fall.

What are symptoms of light deficiency in common sourwood trees?

When common sourwood trees do not receive adequate sunlight, they may exhibit symptoms such as smaller new leaves, leggy or sparse growth with longer spaces between leaves or stems, and faster old leaf drop to conserve resources. Additionally, the tree may experience slower or no new growth, lighter-colored new leaves indicating a lack of chlorophyll, and in cases of excessive sunlight, chlorosis or yellowing of the leaves, sunscald on leaves or stems, leaf curling as a defense mechanism, wilting from increased water loss, and leaf scorching can occur.

How does high temperature affect Common Sourwood and what can be done?

During summer, it is important to ensure that Common Sourwood does not experience temperatures exceeding 35°C. Exposure to temperatures above 38°C can result in lighter-colored leaves, dry and withered tips, and an increased susceptibility to sunburn. To mitigate these issues, any sunburned or dried parts should be trimmed away. Moving the plant to a shaded location or using a shade cloth can further protect it from the harsh midday and afternoon sun. Additionally, watering the plant in the morning and evening helps in maintaining soil moisture, essential for the plant's well-being during high temperatures.