Leptospermum

( lep - toh - SPERM - um )

At-A-Glance Information

This genus of evergreen shrubs or trees needs full sun and little to moderate water. They are casual-looking plants have small leaves and produce tiny blooms along branches. Flowers are typically white, red or pink and petals surround a central cone that matures to a woody seed capsule. They are native to New Zealand and Australia and are commonly called Tea Tree because Captain Cook brewed a tea from the leaves and touted it to his crew as a remedy and preventative for scurvy. The popular Tee Tree Oil is made from the leaves of Melaleuca alternifolia, a species of a related genus.

Leptospermum Species and Varietals

The genus Leptospermum is a member of the plant family Myrtaceae, and includes around 100 species or so. The genus was first formally described in 1776 by German father-son botanist team Johann Reingold Forster and Johann Georg Adam Forster. Tea Tree grows best in zones 14-24, though this varies somewhat depending on the species. For more information, see the following descriptions. To find your zone, click here: Zone Map.

Leptospermum arachnoides (Spidery Tea-Tree)
This species is native to the eastern coast of Australia, and has rough bark and green foliage. Flowers are white, and have many protruding stamens. Fruits that follow blooms are hairy.

Leptospermum laevigatum (Australian Tee Tree)
This species grows best in zones 14-24, H1 and H2 and can be grown as a large shrub or a small tree. It reaches 10-30 feet tall and just as wide, with gray-green leaves and white flowers that pop in springtime. Trunks twist and curve gracefully, and branches carry canopies of foliage. Can be used as a windbreak if planted 3-6 feet apart. Variety 'Reevesii' grows to only 4-5 feet tall and wide and has more dense foliage but is not as handsome.

Leptospermum macrocarpum (Leptospermum nitidum 'Macrocarpum')
Gets 3-15 feet tall and wide, and has tiny reddish leaves that mature to purple-bronze. Flowers bloom in springtime and are chartreuse-yellow with a green center. Variety 'Dark Shadows' gets 15 feet tall and 20 feet wide, with burgundy-flushed leaves.

Leptospermum petersonii (Lemon-Scented Tea Tree)
This species reaches 9-20 feet tall and 6-15 feet wide, with an open erect growth. Branchlets are weeping, and create an interesting canopy. Green leaves give off a lemon scent when bruised. The leaves are used occasionally to make tea. Inconspicuous flowers are white.

Leptospermum polygalifolium (Tantoon, Jellybush, Yellow Tea Tree)
This species is a bit wide-ranging in appearance; it can grow to between 3 and 18 feet in height and 1.5 to 9 feet in width, with either an upright or spreading habit. Leaves are deep green and narrow, and flowers are profuse in spring and summer. Blooms are white and smell like honey, and make for attractive additions to arrangements. Variety 'Yarra River' has red leaves and reaches 12 feet tall and just as wide.

Leptospermum rotundifolium 'Manning's Choice'
To 6 feet tall and just a little wider, this species has an arching, spreading habit. Round, tiny leaves and profuse lavender-pink flowers cover this shrub in springtime. Somewhat short flowering period.
Leptospermum scoparium (New Zealand Tea Tree, Manuka)
This species of Tea Tree grows well in zones 14-24, H1 and H2 and has showy blooms in springtime and summer, either single or double, in white, pink or red. Leaves are closely set on branches and are needle-like. Great as container plants. Varieties are outlined below.
'Apple Blossom'
This plant has an upright growing habit to 8 feet tall and wide. Double flowers are pale pink and age to white, leaves tinge pink in fall.
'Burgundy Queen'
This plant has an upright, dense habit to 12 feet tall and 10 feet wide, with double flowers in deep burgundy. Fall foliage is burgundy.
'Crimson Glory'
To 6-7 feet tall and just as wide. Foliage is bronzey and double flowers are crimson.
'Gaiety Girl'
Slow grower to 5 feet tall and 4 feet wide. Leaves are flushed red, and double flowers are lilac-pink.
'Helene Strybing'
Reaches 6-10 feet tall and wide with an open, pleasing habit. Single flowers are a deep pink.
'Horizontalis'
Fast grower to 3-4 feet tall and 12 feet wide. Branches are horizontal and branchlets droop off of them. Flowers are white and single. Great as a bank cover.
'Pink Cascade'
This plant reaches a foot tall and 3-4 feet wide, with single pink flowers. Branches take a weeping habit; this variety is great for spilling over walls and among rocks.
'Pink Pearl'
6-10 feet tall and 5-8 feet wide. Buds are pale pink and open to reveal double blush pink to white flowers.
'Ruby Glow'
Compact, upright grower to 6-8 feet tall and 4-5 feet wide. Foliage is dark and flowers are double red. The entire shrub looks red when it is in bloom.
'Silver and Rose'
Profuse rose-pink flowers with green centers and bright gray-green foliage on a 4-5 foot plant.
'Snow White'
Spreading, compact grower to 2-4 feet tall and 4-5 feet wide. Double flowers are white with green centers.

Caring for and pruning leptospermum shrubs

These shrubs prefer well-draining slightly acidic soil and like to be planted in a full sun to partial shade location. They are relatively easy-care plants, needing regular water during their first year, and are drought tolerant at maturity. Allow the top few inches to dry out between waterings, and deep water during times of heat and dry weather. These shrubs can be thinned out to create a more attractive habit, but otherwise leave them alone as far as pruning is concerned. They have an attractive natural habit. New growth is unlikely to sprout from old, bare wood, even if it is pruned. After flowers have faded, Leptospermum shrubs can be lightly pruned to encourage a neater look and a bushier growth habit. Fertilize in springtime with a slow-release balanced fertilizer. 

Propagation

​Leptospermum can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your shrub, follow the instructions below:

Propagating Leptospermum by Cutting
  1. Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
  2. In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
  3. Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots. 
  4. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.

Propagating Leptospermum by Seed
  1. Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
  2. Harvest your seeds. The seed pods are pretty easy to spot, they're round and sit on the branches, left behind after flowers have faded (they look a little like buttons). Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
  3. Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7-28 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
  4. Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.
Leptospermum seed pods are round and look like little buttons.
Leptospermum seeds are released from the seed pods when they have dried and begun to split open, as in the photo above.

Problems and Pests

Leptospermum shrubs are relatively pest and disease-resistant. For information on commonly encountered pests and diseases in the home garden, consult the following pages:
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Gallery

These shrubs can be shaped, though they are best left to their own natural habits.
Although the individual flowers on these shrubs are small, they bloom in great numbers and really put on a show.
There are many different forms and sizes of Leptospermum to choose from.

Videos

How to grow Leptospermum shrubs.
How to prune Leptospermum.

Resources

How to Grow and Care for New Zealand Tee Tree
Wikipedia: Leptospermum scoparium
Wikipedia: Leptospermum
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Pages 405 - 406, Leptospermum
If you have any questions, comments, concerns, or photos you’d like to add to the gallery, please let me know by sending me a message using the button below!
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