Bottle brush tree freeze

Scientific Name(s): Callistemon spp.
Abundance: common
What: leaves, flowers
How: tea, seasoning
Where: dry sunny yards, landscaping
When: all year
Nutritional Value: flavanoids
Medicinal Summary:
Leaves/Flowers – antifungal; antibacterial; antioxidant; cough suppressant (tisane)
Bottlebrush tree

Close-up of opened flowers.

Close-up of closed flowers.

Close-up of leaves.

Close-up of branch with woody fruit.

Bottlebrush branch.

North American distribution, attributed to U. S. Department of Agriculture.

Used often as a decorative landscaping tree, the striking red blossoms of the bottlebrush tree offer more than visual beauty. Their aroma is invigorating, somewhat minty or menthol in nature. The trees are small, rarely more than 15′ tall and equally as wide. The leaves are evergreen and the blossoms also last can be found on the tree almost all year round. These flowers really explode vigorously in mid-spring and are often swarmed with bees who know a good thing when they smell it!
Both the flowers and leaves can be used to make an aromatic tea. The fresh blossoms do give a sweeter flavor than leaves. Aging the harvested leaves for two weeks helps as this breaks down the cell walls, allowing more of the flavorful compounds to escape into the tea. Flowers, being more delicate, do not benefit any from being aged and ideally are used fresh off the tree.
You can also use the leaves and flowers of the bottlebrush tree similar in manner to bay or rosemary leaves. Add several to a sauce, stew, or roasting meat to add an exotic flavor.
Mashed bottlebrush leaves rubbed on the skin is reported to keep away insects. This property may also be used to keep clothes, bedding, and houses bug free by laying sprigs of the leaves around whatever you want protected.
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I have to admit that this is one of my favorite plants. I love, love, love the Bottlebrush plant. This plant is truly a carefree plant with little to no worries about diseases or bug problems. It will flower several times a year here in the south, (I live just outside of Houston, Texas). The Bottlebrush is great for covering things and blocking views, such as a fence, or blank wall, or a bright light from a neighbor’s flood light attached to the back of their garage. The last example is what happened to us. The light was so bright that it lite up over half of my backyard and shined into my son’s bedroom window. We put up a bottlebrush to screen out the light. It grew nicely over a short period of time and is beautiful when it blooms.
Another great thing about this plant is that there is very little pruning involved in taking care. It is best to trim it to shape it. Try not to take out too much out of the center of the plant.
The ins & outs of the Bottlebrush:

Scientific name: Callistemon rigidus
This is native to Australia.
Growth Habit: Zones 8-10
Grows 8 x 6 feet; the average growth is 6 x 4 feet (but I have seen it grown to about 11 feet)
Flower: Bright red spikes near the tips of the branches, each flower sessile, in axil of floral leaf. Many
bristlelike stamens one inch or more long. Flowers grow in a mass in the shape of a bottlebrush,
hence the name. It flowers in late spring and early summer and then again in the fall.
Foliage: The leaves are a gray-green leaf scattered along woody stems. Each leaf is 2 to 5 inches long and
about 1/2 inch wide. They have a midvein that runs through the middle. The tips of the leaves are
sharp-pointed. The new foliage is showy being reddish green.
Pros: -Drought tolerant.
-The bottlebrush plant attracts hummingbirds and butterflies, as well as bees (this is a good thing).
-Bottle brush have wonderful flowers that are very showy when in bloom.
-These shrubs and small trees are salt tolerant, which makes them great for near the beach.
-Non-toxic to dogs, cats, and horses.
-Very little care to keep this plant a beauty, mild pruning.
Cons: -The bad thing about these plants is that they will freeze when there is a severe winter. I personally
have not lost any of these plants but they have died back to the ground during a hard winter.
-If you don’t trim them occasionally, the ends of the branches can bend down instead of staying
upright. The flowers tend to be heavy and makes the branches droop on smaller branches.
-Bottle brush plants do not want to be in poorly drained soils.
Other common species: -‘Little John’- a dwarf red
– ‘Splendens’- a scarlet-red
-‘Hannah Ray’- an orange-red
-Callistemon citrinus- Lemon bottlebrush lemon-scented leaves; red flowers.
-Callistemon viminalis- Weeping bottlebrush, red flowers.

Q: I see tall bottlebrushes in bloom, but they are too large for my garden. Is there a dwarf bottlebrush?

F.M., Houston

A: Yes. You’ll get lots of flowers on Callistemon sp. ‘Little John,’ a 3- to 4-foot bottlebrush with aromatic, dense green foliage and spring-to-fall bright red flowers, which attract hummingbirds and butterflies. This shrub likes sun to part sun and a well-draining, organically enriched soil. Mulch with compost or bark mulch.

Given an organic soil, it shouldn’t require additional fertilizer. But you can apply a slow-release balanced product such as an 8-8-8. Fish emulsion also works. This plant is drought-tolerant once established.

Q: What is the large shrub/small tree with white blooms and large red stamens?

M.M., Houston

A: It’s pineapple guava (Feijoa sellowiana), a handsome evergreen shrub that works well as a specimen plant or as a hedge in multiples. New silvery foliage matures to a blue-green with gray undersides, providing a nice backdrop for the white blooms with prominent red stamens in spring. The fruit that follows the flowers makes a great jelly, and the wildlife enjoy it, too.

Q: What are the chances of successfully growing pomegranate trees in the Rosharon area? Our soil is heavy black clay that has been amended with gypsum and compost. Our place is fenced to keep the deer and hogs out, but we do have squirrels.

B.D., Rosharon

A: I think the odds are good. Plant in a sunny, well-draining area.

Pomegranates need some cold to produce August-September, so look for low-chill varieties (150-200 hours). Self-fruitful ‘Garnet Sash’ is a vigorous producer of large, dark-red fruit. Self-fruitful ‘Red Silk’ is a 6-foot-tall heavy producer of medium-large, pinkish-red fruit. And self-fruitful ‘Pink Satin’ has medium to large fruit with dark-red flesh and pink edible seeds.

Antioxidant-rich pomegranate juice can be used in drinks, syrup and jelly. The fruit can be eaten fresh or cooked; the plentiful seeds are sweet.

Q: I hung hummingbird feeders mid-April, but I haven’t seen any birds yet. Are they late?

G.A., Houston

A: I haven’t seen any birds either, and other gardeners have reported seeing few or none. I wondered if a lack of nectar plants due to the cold winter was a factor, so I asked naturalist and Houston Chronicle columnist Gary Clark to share his thoughts:

“No, the hummers are not late, and late winters do not forestall their migratory drive. It may be that the loss of some nectar plants kept some of them from sticking around for a few days, but that would be mere speculation. We had plenty of them at our house, but we have two constantly filled hummingbird feeders.

“In spring, ruby-throated hummingbirds move through rather quickly to get to more northerly breeding grounds, which, by the way, include parts of East Texas. So, even in good flowering times, we may not notice them that much in spring. I saw them along the coast beginning in late March, so I know they were coming through as usual.”

Late summer through fall, when hummingbirds linger in the area to fatten up for their trips across the Gulf of Mexico, is a better time to spot them, Clark added.

Q: I grow some vegetables in the garden and some in planters. I use Medina organic granular fertilizer on the plants in the ground and Miracle-Gro soluble fertilizer on the potted ones. Would the Medina work on container plants? The instructions call for 1 tablespoon every two months on potted plants. Since we water pots daily, should I apply every month?

P.D., League City

A: The organic fertilizer should be fine for the containers. And, yes, because we do have to water frequently in our climate, nutrients leach more rapidly. You might step up the fertilization, especially when growing vegetables. Adjust applications according to plant vigor.


Callistemon rigidus

There are lots of different species, varieties, and cultivars of bottlebrush, an Australian native, so do a little research on the differences before you buy.

The two most important distinguishing characteristics are size and hardiness, since dwarf cultivars and more cold tolerant species are becoming more widely available.

Bottlebrush is a small, usually shrubby tree, normally getting only 10 to 15 feet tall. Bees absolutely love the fuzzy red flowers and the tree will be buzzing with life all summer long.

This tree is notoriously frost sensitive, usually being completely killed if temperatures get into the 20s. But I’ve also seen bottlebrush taken out by our extreme Texas heat during abnormally hot, dry summers.

One way to protect bottlebrush from the heat is to plant it in a sheltered spot, with maybe only 6 to 8 hours of summer sun.

And the north side of a landscape should be avoided, since that’s the coldest spot. Local garden blogger Dr. Robin Mayfield shares her story of her beloved specimen. After the harsh summer of 2010, which was followed by an abnormally cold winter, her majestic 12 foot tree succumbed to the stress of such extreme weather, but she loved the tree so much, she’s decided to plant again this year, in a different spot in her yard.

Bottlebrush is evergreen, so it’s a good choice for screening out unsightly views. But since it’s wispy, it allows light to filter through, rather than creating a solid hedge-type feel, giving privacy without overwhelming an area.

Robin reports that her trees were very drought tolerant once they were established, and were very happy in her unamended heavy clay soil.

So, final analysis: lovely tree that brings on the bees for months in warm weather. But, it needs good drainage, sunlight but not searing, and we can lose them in cold winters.


The temperature of 16 degrees on the night of Jan. 5 is the lowest one in the past 27 years I can recall, but it was still in the normal range for our growing zone.

Winter low temperatures can reach 15 degrees in USDA Zone 8b, which includes all coastal counties plus the southern half of the Savannah River Valley in South Carolina, (

Snow is an excellent insulator. The snow that covered the ground before air temperatures fell to 20 degrees or lower helped to keep soil from freezing. At the Clemson Coastal Research and Education Center in West Ashley, the soil 2 inches deep stayed 33 to 36 degrees between Jan. 3 to 7.

Temporarily disfigured

The broadleaved evergreen trees and shrubs that are so characteristic of the Lowcountry landscape are the plants most severely damaged by unseasonable cold. Plants suited for Zone 8 should have survived the recent extended cold period. However, surviving might mean that the crown and roots survived but not the tops.

Damage to cold-sensitive evergreen shrubs such as oleander and bottlebrush will be obvious as dry, dull green or brown leaves. Oleander may be killed back to the ground, while the lower 2 to 3 feet of bottlebrush stems likely survived.

Sago palm is one of the most cold-sensitive Lowcountry ornamentals. Whenever temperatures go below 30 degrees, plants need to be protected with a thick blanket or very large piece of fleece fabric.

Patience with pruning

Homeowners should not be in a hurry to prune shrubs after the cold spell. Pruning, especially tip pruning, stimulates buds lower on the branch to develop. These new leaves are particularly cold sensitive, even if the mature shrub can tolerate cold.

Evergreen shrubs damaged by cold should not be pruned until they produce new shoots, when dead branches can be removed right above the fresh growth. Dead leaves on sago palms can be removed once the danger of frost is past on March 20.

If, or how much, damage was done to deciduous shrubs will be apparent when they leaf out in February or March. Regardless of the winter temperatures, deciduous shrubs and trees should be pruned starting the third week in February.

This standard recommendation for the lower half of South Carolina is based on expected low temperatures. After mid-February, temperatures below 27 degrees are not common, so freshly cut wood will not be damaged by cold. (The 24 degrees on March 16, 2017, was a notable exception to this rule of thumb.)

Evergreen plants that survived the cold will expend energy this spring replacing lost leaves or branches. They should be fertilized in early March with the normally recommended rate but not more.


Horticulturists classify tender perennials as herbaceous ornamentals that do not survive temperatures of 27 degrees. While these plants may survive some Lowcountry winters, they are not likely to emerge this spring.

This group of popular flowers includes African daisies, bush daisy (Euryops pectinatus), Chinese hibiscus, hybrid lantana, plumbago, princess flower (Tibouchina urvilleana) and some salvias, such as ‘Indigo Spires’ and cultivars of Texas sage (Salvia coccinea) such as ‘Lady in Red.’

Dead foliage can be removed now, but plants should be left in place until April 15 to be sure they are dead before a plucky survivor is removed by accident.

In general, foliage of spring-blooming bulbs, other than amaryllis, is quite cold tolerant. Several of my daffodils and spring star flower (Ipheion uniflorum) had emerged before the ice and snow arrived. Digging through the snow left in my backyard revealed still green foliage of spring star flower and the early blooming daffodil ‘Flore Pleno’ and green shoots of ‘Saint Keverne’ daffodil.

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Winter vegetables, herbs

At Clemson Coastal Research and Education Center, older leaves on kale, arugula, red beet, carrot, leaf lettuce and romaine were damaged, but the younger leaves were fine. Lower leaves on parsley, cilantro, fennel and lemon balm also survived. Soft, browned foliage of vegetables, herbs and winter annuals should be removed immediately to prevent rotting of the remaining plant.

Collards are one of the most cold-tolerant winter vegetables. Leaves exposed to temperatures below freezing take on a purplish hue but rarely are browned. Collards exposed to cold are still edible, and many people prefer their sweeter taste.

Although rosemary and bay are cold-tolerant perennial herbs in South Carolina, the foliage often suffers from chilling injury. They should be handled as other evergreen shrubs mentioned above.

Five inches of snow doesn’t translate directly into five inches of water that soaks into the soil. Some snow will turn directly into water vapor without first melting, a process called sublimation. To avoid compacting soil, don’t walk on or dig in wet soil until it drains and dries. If soil must be worked to plant early spring vegetables, temporarily remove any mulch to speed drying.

Snow lessons

Snow that lingered on the north sides of buildings or other shady spots is a good indication of microenvironments where temperatures are slightly colder than other portions of the yard. These spots should be avoided when tender perennials or shrubs are added to the landscape.

Likewise, sunny spots where the snow melted first are an indication of warm niches where cold-sensitive plants may have that bit of extra protection they need to survive over winter. I deliberately planted a Lemmon marigold on the southwest side of my garage, a warm, protected spot.

Leave the loppers in the garage until the end of February. This winter’s cold weather may not be over.

Anthony Keinath is professor of plant pathology at the Clemson Coastal Research & Education Center in Charleston. His expertise is in diseases of vegetables. He is also an avid gardener. Contact him at [email protected]

Plant-by-plant freeze information

  • Photo: Douglas Freer, /

Photo: Douglas Freer, / Image 1 of / 1



Image 1 of 1 Photo: Douglas Freer, / Plant-by-plant freeze information 1 / 1 Back to Gallery

Geraniums, petunias



Blooms suffer some damage in the 20s, but the plants generally survive.

Impatiens, waxleaf begonias, crotons, zinnias

Will suffer considerable top damage, and with sustained below-freezing temperatures, they’ll die. After a freeze, remove soggy, freeze-damaged plant material from soft-stemmed plants.

Alyssum, calendula, cyclamen, dianthus, pansies, stock

Can survive a dip into the 20s without cover.

Ornamental kale and cabbage

Can survive a dip into the 20s without cover. Cold temperatures enhance the color in ornamental kale and cabbage.

Hibiscus, oleanders, duranta

Wait until there’s no danger of frost to prune these damaged shrubs. The damaged material will offer some protection to the live wood farther down the branch should we have another freeze. Once there’s no danger of a freeze, prune down to the firm, green area of each stem or branch.

Brugmansia, or angel’s trumpet

Will suffer top damage but returns from mulched roots in the spring.

Ligustrum, Indian hawthorn, boxwood, roses

Many shrubs will withstand freezing temperatures, and unless temperatures are expected to drop into the low 20s or teens, few cover these shrubs.


Some gardeners cover azaleas, especially when in bloom, during a hard freeze. The plants will survive covered or not, but frost will ruin any flowers.

Hamelia (hummingbird bush) and duranta (golden dewdrop)

May suffer damage to tops during a freeze but will return from the roots in spring. Don’t bother covering these, since they become quite large during our long growing season.


While tropical hibiscus are best protected in winter, root-hardy hibiscus planted in the garden are generally allowed to die back, then return in late spring.


Bottlebrush, a favorite with hummingbirds, can suffer considerable damage when temperatures drop into the low 20s, so it is a good idea to grow it on the south side of the house.


Dont’ tolerate freezing weather.

Avocado, guava, jaboticaba, mango and starfruit

These tropicals tolerate temperatures to 27 degrees


These are among the most cold-hardy citrus for our area and can be root-hardy into the low 20s, but protection of top growth is sometimes necessary to help ensure blooms.

‘Meyer’ lemon

Cold hardy to the mid 20s.

Citrus in general

You can help protect your citrus through the winter by mounding soil over the graft union in the fall and removing it in the spring after danger of a hard freeze has passed.

Tropical fruits

Broadly, most tropical fruits are safe within 12 miles of the Gulf and in the Hermann Park area. In most other parts of urban Houston south of I-10 and inside the loop (perhaps even to Hobby), tropicals will do well in protected areas. In other parts of the Metro region, increasing amounts of winter protection will be necessary as the location gets more rural and further from the Gulf.

Norfolk pine

With plenty of winter protection, Norfolks could possibly survive Zone 9 temperatures, which dip into the 20- to 30-degree range. The Houston area lies on the Zone 8-9 border. In Zone 8, low temperatures can drop between 10 and 20 degrees. At 32 degrees, damage to the growing points will occur; below 25 degrees, severe freeze damage occurs.

Skyflower vine

Skyflower (Thunbergia grandiflora) will freeze to the ground during a cold winter, so mulch to protect roots. It should return from the roots in spring.


Often called the flamboyant tree, it is usually listed as cold-hardy only as far north as Zone 10. Our growing area covers Zones 8b/9a.


Lantana is usually root-hardy and will pull through a cold snap. Mulch helps.


Cannas are typically root-hardy; mulch helps.


Crotons can be pretty tender, and a prolonged freeze will usually do them in.

Purple fountain grass

It’s an annual since it’s not root-hardy in a hard freeze, but many return year after year. A prolonged freeze will kill it.

Bird of Paradise

May survive a dip to the mid-20s, but it’s best to protect it during freezing weather.


Should top growth be damaged during a freeze, leave all or at least a good deal of dead wood until we’re out of the danger of frost. Those gardeners with container-grown bougainvillea sometimes prune long stems for easier storage in a garage or sheltered area in winter.

Don’t see the plant you’re looking for? Leave your plant in the comment area below, or e-mail [email protected]

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