Buddleja alternifolia, known as alternate-leaved butterfly-bush, is a species of flowering plant in the figwort family, which is endemic to Gansu, China. A substantial deciduous shrub growing to 4 metres (13 ft) tall and wide, it bears grey-green leaves and graceful pendent racemes of scented lilac flowers in summer.
Alternate-leaved butterfly-bush is fairly disease-resistant and typically does not suffer from many diseases. Care-wise, this plant is relatively low-maintenance. When grown outdoors it needs little watering, and larger specimens generally do not require pruning. Smaller plants, however, should be pruned after they have finished blooming. Alternate-leaved butterfly-bush is well suited to anyone with outdoor space, such as a garden or deck, and does not demand extensive gardening experience.
How to keep Buddleja Alternifolia.
Light
Alternate-leaved butterfly-bush prefers a setting with abundant sunlight throughout the day. Although it can endure spots that receive sun for only part of the day, its growth may be less vigorous. In its native range it prospers in full sun. Both too much and too little sunlight can stunt the plant's development.
Water
The alternate-leaved butterfly-bush thrives in well-drained soil and requires moderate moisture. It benefits from weekly watering. Typically grown outdoors, this deciduous plant sheds its leaves annually, which affects its water uptake depending on the season.
Temperature
Alternate-leaved butterfly-bush is native to areas where temperatures generally range from 41 to 95 °F (5 to 35 ℃). The plant favors cooler conditions and may need extra care in warmer regions. In periods of extreme heat, consider giving it shade or moving it indoors.
Fertilizer
The timing of fertilizing the Alternate-leaved butterfly-bush is important. Apply fertilizer in early spring and repeat monthly until early summer. Fertilizer promotes attractive blooms and supplies energy during both dormant and active growth phases.
Pruning
The alternate-leaved butterfly bush showcases graceful, cascading branches adorned with fragrant purple flowers. To maintain the plant's health and encourage vibrant blooms, prune it in early spring. Trim back the old wood by one-third and remove any dead branches. Avoid pruning after the flowers have bloomed, as this can diminish next year’s blooms. Proper pruning promotes air circulation and results in a lively, flourishing plant.
Pot & Repot
Repot the alternate-leaved butterfly bush every 2-3 years in early spring to encourage healthy growth. When repotting, choose a larger container and place the plant in a well-lit area. After repotting, water it moderately. This plant's hardiness makes it easy to care for, and it serves as an attractive addition to your garden, drawing butterflies to its blooms.
Botanical profile.
- Plant Type
- Tree, Shrub
- Life Cycle
- Perennial
- Genus
- Buddleja
- Family
- Scrophulariaceae
- Hardiness Zone
- 5-9
- Mature Height
- 3.05 m to 5.18 m
- Mature Spread
- 2.44 m to 3.05 m
- Leaf Color
- Green, Gray, Silver
- Leaf Type
- Deciduous
- Flower Color
- Lavender, Purple
- Flower Size
- 2.54 cm
- Bloom Time
- Mid spring, Late spring, Early summer
- Planting Time
- Spring, Summer, Autumn
- Harvest Time
- Mid summer, Late summer, Early fall
- Native Area
- China
Other names.
Reader questions.
How should I water my Alternate-leaved butterfly-bush?
To promote excellent root development, place a garden hose at the base of the plant, but avoid spraying the leaves directly. If the leaves are outdoors and facing direct sunlight, they will need more watering. Consider using bubblers or soaker hoses to moisten the roots of each plant or cover the entire garden. Remember to drain any excess water and wait for the soil to dry before watering again. Water at ground level to prevent diseases. On a sunny day, you can spray the entire bush with water. Whether potted or in-ground, the Alternate-leaved butterfly-bush prefers deep watering over light sprinkling.
Why is it important to add fertilizer to my Alternate-leaved butterfly-bush?
To help your Alternate-leaved butterfly-bush thrive and produce beautiful blooms, it is important to fertilize it. Fertilizing in early spring is especially beneficial as it ensures excellent flower growth during that season. Additionally, fertilizer provides the plant with energy to store in the ground during dormant phases, helping it sustain growth when active periods resume in the fall or late spring.
What are the sun requirements for an Alternate-leaved butterfly-bush?
The Alternate-leaved butterfly-bush requires abundant sunlight exposure throughout the day to flourish optimally. It can survive in areas with partial sunlight but will not grow as vigorously. Native to habitats bathed in full sunlight, the plant may not develop properly if it receives too much or too little light. Remember, it's crucial to monitor the movement of sunlight in your garden and select locations that provide a harmonious mix of light and shade to ensure the well-being of your plants.
What is the native climate for Alternate-leaved butterfly-bush?
The Alternate-leaved butterfly-bush (Buddleja alternifolia) is native to regions with temperatures ranging from 41 to 95 °F (5 to 35 °C). It prefers cooler climates and may need extra care in warmer zones. In case of extreme heat, providing shade or moving the plant indoors can be beneficial. The plant also has a strong resistance to cold and usually does not require special frost protection measures. However, in winters where temperatures are expected to drop below -25°C, it's important to wrap the trunk and branches with non-woven fabric or cloth to provide cold protection. It's also recommended to water the plant abundantly before the first freeze in autumn to ensure the soil remains moist and enters a frozen state, which aids in preventing drought and water scarcity during winter and early spring.
What should I do if I give too much or too little water to the Alternate-leaved butterfly-bush?
An overwatered Alternate-leaved butterfly-bush will exhibit signs such as yellowing leaves, leaf drop, and wilting. The plant might also appear dull and unhealthy, with mushy stems. When these signs start to show, it is recommended to adjust your watering schedule if possible. However, wilting can also be a sign of under watering. In this case, the leaves will become crispy and dry. Check the soil and if it is dry, a thorough watering is needed. Sufficient water will help the plant recover, but it may still have dry appearance and yellow leaves due to damage to the root system. Once the plant returns to normal, the yellowing of leaves will cease. Indoor Alternate-leaved butterfly-bush plants should be checked for moisture levels and avoid overwatering. Look for signs of black spots which indicate the need for the soil to dry out before watering again. Overwatering can lead to root rot, so if discolored and slimy roots are found, consider transferring the plant to a different pot. Always prevent root rot by avoiding overly soggy soil. When planting the Alternate-leaved butterfly-bush outdoors, dig a bit deeper and if the soil feels too dry, it could indicate underwatering. Adequate watering is crucial for the plant's recovery.
When should I fertilize my Alternate-leaved butterfly-bush?
Timing is crucial for fertilizing Alternate-leaved butterfly-bush. Applying fertilizer too early while the bush is still dormant is ineffective as it will be washed away by rainwater, leading to waste and pollution. The first application of fertilizer should be in early spring, with subsequent applications once a month until early summer.
How does artificial lighting affect the growth of indoor plants?
Indoor plants, including the Alternate-leaved butterfly-bush, require adequate lighting for healthy growth, especially when natural sunlight is limited, like in winter or in less sunny indoor spaces. Artificial lights, such as LED lights tailored to emit specific wavelengths, play a critical role in supporting plant growth under these conditions. For optimal growth, full sun plants need 30-50W/sq ft of artificial light, partial sun plants require 20-30W/sq ft, and full shade plants need 10-20W/sq ft. The light source should be placed 12-36 inches above the plant, mimicking natural sunlight as closely as possible. Furthermore, the duration of artificial lighting should align with the natural daylight hours needed by the plant species, typically between 8-12 hours per day.
How does low temperature affect Alternate-leaved butterfly-bush and what are the solutions?
Alternate-leaved butterfly-bush thrives best in temperatures above 5°C and should be kept above -20°C during winter. If temperatures fall below -25°C, the plant's branches may become brittle and dry by spring, with no new shoots emerging. To address this, any dead branches that have failed to produce new leaves by spring should be pruned away. This helps in maintaining the health and appearance of the plant.
How often do I need to give water to my Alternate-leaved butterfly-bush?
The Alternate-leaved butterfly-bush prefers deep and infrequent watering. If you have them in pots, make sure to soak them with a gallon of water each time as the water storage in pots is limited and the soil dries out faster. In colder regions, water every 3 to 5 days, preferably in the morning when the soil is dry. Check the soil inside the pot - if the top 2-3 inches are dry, it's time for a full watering. On hot days, monitor the moisture daily since the heat can quickly dry out the pot's soil. For garden plants, irrigation is necessary. In hot climates, water once a week, but only when you see that the top 2-3 inches of soil are dry. Take into account rainfall and avoid overwatering to prevent root rot. The Alternate-leaved butterfly-bush typically grows in spring and fall. For outdoor plants, adding 3 to 4 inches of mulch helps conserve water. Sandy soil drains faster, so water more frequently. Clay soil, on the other hand, requires less frequent watering. You can mark the watering dates on a calendar and keep an eye on the plant's leaves - drooping leaves might indicate that watering is needed.
When is the best time to not fertilize my Alternate-leaved butterfly-bush?
To ensure optimal growth and blooming of the Alternate-leaved butterfly-bush, it's important to be mindful of the type and timing of fertilizer used. Avoid using a fertilizer with high levels of nitrogen, as this can result in excessive leaf growth but sparse blooms. Instead, opt for a fertilizer that contains a lower amount of nitrogen compared to other nutrients. It's also crucial to refrain from fertilizing after the early autumn, as this can promote excessive growth just before winter, which is not desirable. Additionally, it's best not to fertilize the butterfly-bush during hot and dry periods, as dry soil cannot effectively deliver the fertilizer and it may lead to stimulation of growth that requires additional water, which may not be readily available. It is recommended to apply the fertilizer earlier in the season when temperatures are cooler. Lastly, it's important to note that the Alternate-leaved butterfly-bush can absorb fertilizer from nearby plants or lawns, so be cautious to avoid inadvertently providing the tree or shrub with a double-dose of fertilizer.
What are the symptoms of insufficient or excessive sunlight in Alternate-leaved butterfly-bush?
The Alternate-leaved butterfly-bush may show several signs of distress due to inadequate or excessive sunlight. Symptoms of light deficiency include smaller new leaves, leggy or sparse growth, accelerated leaf drop, halted growth, paler new leaves, and a general appearance of weakness. On the other hand, excessive sunlight can lead to chlorosis (yellowing leaves due to chlorophyll breakdown), sunscald, leaf curling as a protective measure, wilting from excessive water loss, and leaf scorching characterized by brown, crispy leaf edges. These symptoms indicate the plant's struggle to adjust to its lighting environment.
What should be done if an Alternate-leaved butterfly-bush experiences high temperature?
During summer, it is ideal to keep the Alternate-leaved butterfly-bush below 35°C. Temperatures exceeding 38°C can cause the leaves to lighten in color, tips to become dry and withered, and increase susceptibility to sunburn. To remedy this, trim away the sunburned and dried parts of the plant. Moving the plant to a shaded location during the midday and afternoon sun or using a shade cloth can provide necessary protection. Additionally, watering the plant in the morning and evening helps keep the soil moist, alleviating some of the stress caused by high temperatures.