Lavender plant care: tips for pruning, watering & more
A lavender tree is a beautiful tall lavender plant with aromatic gray-green leaves and clusters of fragrant purple flowers growing on erect stems. Also called lavender topiary, the plant is a traditional lavender shrub trained to grow as a tree. Lavender trees are ideal for growing in pots indoors or outdoors. Growing tall in pots, a lavender tree fills rooms or gardens with heavenly aromas and beautiful purple and green colors.
Growing a potted lavender tree requires regular pruning but minimal care. The bushy lavender tree with its upward growing leafy stems and purple blooms requires plenty of sunlight, little watering, and average soil. Therefore, caring for a lavender tree is relatively straightforward if you get these factors right.This article is a complete guide to growing a lavender tree in your home or garden. You will also find helpful tips on caring for a potted lavender topiary tree so that it thrives for many years.
What is a Lavender Tree (Lavender Topiary)?
A lavender tree is the classic lavender plant pruned and trained to grow tall. Lavender topiary fans commonly use Spanish lavender to create lavender trees that grow in pots.
Lavender trees can grow 2 to 3 ft. (0.6 – 1 m) tall. However, depending on the pot size, the purple flowering tree can seem taller. The bushy lavender crown can measure up to 2 ft. (0.6 m) wide. However, pruning fragrant leafy stems and purple flowering spikes can help to manage its size.
A lavender tree has a bare wooden stem topped with a bushy crown of grayish-green slender lavender leaves. When in bloom, the lavender tree has a mass of purplish or lilac conical or cylindrical spikes growing on tall stems.
If you care well for a lavender tree, it can grow for around five years.
The benefit of growing a lavender tree is that you can enjoy all the wonderful features of the classic lavender shrub —beauty, aroma, and attractive purple or lilac flowers. However, a lavender tree is more versatile and ideal for container gardens, patios, balconies, or beside a sunny window indoors.
Lavender trees are evergreen purple perennials that come back year after year. In USDA zones 7 through 9, lavender trees grow outdoors throughout the year. Spanish lavender trees won’t perform well in colder regions. Therefore, the low-maintenance shrub may need overwintering indoors to prevent frost damage.
How to Grow a Lavender Topiary Tree
The easiest way to grow a lavender tree is to buy a small plant from a nursery and prune the stems to develop a tree-like shape. You should remove the side stems, leaving the strongest central stem to form into a tree. You can also start lavender topiary by growing the tree from cuttings.
To start growing a lavender tree, trim out the plant’s lower side shoots and stems. You should then be left with the main shoot or stem with leafy growth further up. Next, place a bamboo supporting cane in the pot and tie the small lavender tree to it.
After pruning the lavender plant into a tree shape, the next step is to care for it well so that it grows into a two or three-foot tree. Ideally, the pot for a lavender tree must have drainage holes and should be 2” (5 cm) larger than the root ball. This prevents too much moisture from damaging the lavender tree’s roots.
How to Care for a Lavender Tree
Grow a lavender tree in well-draining soil amended with perlite for extra drainage. Growing indoors or outdoors, place the lavender tree pot in full sun, so it gets at least six hours of sunlight daily. Water the potting mix when the top 1” (2.5 cm) of soil is dry.
Regular lavender tree care also involves regular pruning. After the tree is established in a pot, you need to trim stems that begin to dangle down. You can also encourage bushier growth by cutting back a few inches of stems but avoid cutting any woody parts.
Growing Potted Lavender Tree Indoors
To care for a lavender tree indoors, grow the potted lavender plant near a window that gets four hours of direct sunlight daily. Plant in well-draining, loamy potting mix, and water the lavender tree when the top layer of soil dries. Keep humidity low and average room temperature for best growth.
Here are some tips on growing a lavender tree in pots at home:
Keep room temperatures between 65°F and 70°F (18°C – 21°C).
Ensure humidity is below 40 percent.
Provide plenty of air circulation.
Use a slow-release fertilizer once a year in the spring.
Never allow the soil to dry completely out or become too soggy.
Caring For Lavender Tree Outdoors
To grow a potted lavender tree outdoors, place the plant in a sunny spot where it gets six to eight hours of sunlight. Use a sandy potting mix that drains quickly and add a tablespoon of lime. Check the soil regularly and water thoroughly when the top 1” (2.5 cm) is dry.
If you live in zones 7 to 10, a lavender tree will perform well growing in the ground. The planting area must be well-draining, and a raised bed is ideal for growing a lavender tree. The soil should be slightly alkaline and be low to moderately fertile. Only water the lavender tree enough to keep the soil moist without becoming overly damp.
How to Overwinter Lavender Tree Indoors & Outdoors
Taking the potted lavender tree indoors is usually recommended during harsh winters. Lavender grows best in the heat. Therefore, in colder climates — zones 6 and below — you’ll need to overwinter a lavender tree indoors.
When the outside daytime temperature drops below 60°F (15°C), bring the potted lavender tree indoors for a few hours and place it near a sunny window. Repeat this process for a week, gradually increasing the time. This helps the tree adjust to new conditions. Then after a week, you can keep the lavender tree indoors in a sunny location.
To care for a lavender tree overwintering indoors, only water the plant occasionally. The goal is to prevent the potting soil from completely drying out. You should also rotate the plant by one quarter every week to provide enough sunlight and air.
In spring, when the risk of frost has passed, you can start to acclimatize the lavender tree by moving it outdoors. You should take the potted lavender plant outside for a few hours each day, place it in a sunny spot, and protect it from the wind. After a week, you can leave the lavender tree to grow outside.
Lavender Tree Care Guide
Let’s look in more detail at how to care for a lavender tree.
Where to Grow Lavender Topiary Tree
Lavender is native to the Mediterranean region and needs plenty of sunlight and relatively arid conditions to thrive. When choosing where to grow a lavender tree, select the sunniest spot in your home or garden. Too much shade will result in leggy growth and no flowers.
Another consideration when choosing the ideal spot to grow a lavender topiary tree is air circulation. To avoid foliar fungal growth or other humidity-related issues, make sure plenty of air can circulate around the plant.
Where to grow a lavender tree indoors: Place the potted lavender tree beside a south-facing or west-facing window so that it gets four hours of sunlight. Ensure the room is well-ventilated and temperatures are at least 70°F (21°C) during the day and between 50°F and 55°F (10°C – 13°C) at night.
Where to grow a lavender tree outdoors: Put the lavender tree pot in the sunniest part of your garden. As long as the foliage has enough air circulation, you shouldn’t have to worry about humidity. However, in warm, humid climates, you should ensure plenty of airflow around the plant.
The Best Potting Mix for Growing a Lavender Tree
A lavender tree grows best in a well-drained, loamy or sandy soil that is slightly alkaline. Combine two parts of potting soil, one part gravel, and one part perlite. Then add a tablespoon of garden lime to create a somewhat alkaline mix. This type of potting soil is similar to the soil conditions where lavender plants grow.
When to Plant a Lavender Tree
The best time to plant a lavender tree in the ground is in mid-spring. You can transfer a lavender tree from the pot to your garden during April and May. At this time, the ground is warm enough, and the roots will have time to establish themselves. Apart from planting in a sunny location, you must ensure the soil is well-draining.
To check if the ground is suitable for a lavender tree, dig a hole 12” (30 cm) deep and wide. Fill with water and allow it to drain. After 12 hours, refill the hole with water and time how quickly it drains. If the water disappears in 2 to 3 hours, the site is suitable for a lavender tree.
How to Water Lavender Tree
The best way to water a lavender tree growing in pots is to drench the potting soil when it is partially dry. The goal of watering a lavender topiary tree is to ensure the soil is consistently moist but never too damp. To test the soil, poke your finger into it. If the soil is dry to a depth of 1” (2.5 cm), you can water the lavender tree.
The two worst watering mistakes to make with a lavender tree are overwatering it and letting the soil completely dry out. Too much water will cause root rot, and your once beautiful tree will die. Too little water will result in yellow lavender leaves and weak growth.
Top tip when watering a lavender tree outside: Lavender trees growing in pots outdoors dry out faster than in the home. Therefore, you should check the potting soil frequently during hot weather and water as necessary.
Pruning a Lavender Topiary Tree
Proper care of a lavender topiary tree requires regular pruning. Every spring, cut back about one-third of the stems to encourage bushy growth and prolific flowering. In addition, trim of lavender stems that droop to keep the tree-like appearance. This is because lavender tree stems tend to dangle down.
Here are a few pruning tips for growing a lavender tree:
Never cut into woody growth, or the tree will fail to produce new stems.
Deadheading lavender flowers is a good idea. First, you have beautiful aromatic flowers to use in cut flower arrangements or dry them for potpourri. Second, trimming off spent lavender tree flowers encourages a second bloom.
Fertilizing a Lavender Tree
Lavender trees growing in pots grow well in poor to moderately fertile soil. If the tree gets enough sunlight and occasional watering, a lavender plant can grow well without additional fertilization. However, you can apply a diluted fertilizer in early spring and late fall to encourage healthy growth.
Applying too much fertilizer to a potted lavender tree inhibits flowering and encourages leafy growth.
Repotting a Lavender Tree
Lavender trees perform well when slightly rootbound, so you don’t need to repot a lavender tree often. Instead, you can repot a lavender tree every two or three years.
When repotting a lavender topiary tree, always replace the potting mix with a well-draining, slightly alkaline soil. Also, choose a pot that is 1” or 2” (2.5 – 5 cm) larger than its current one.
Because lavender trees can become top-heavy, choosing a sturdy pot that will support its weight is vital. Therefore, to prevent a 3-foot (1 m) lavender tree from toppling over, choose a heavy cache pot made from clay or terracotta. Then you can put the planting pot inside the larger, heavier pot.