Growing zones in the united states

The 2012 PHZM boasts some significant improvements over earlier versions, though they may still not reflect very recent climate changes. Among the improvements:

  • The resolution is noticeably better. Mapping was improved by using a Geographic Information System (GIS). The higher resolution makes seeing the distinction between zones clearer and easier. It also makes it possible to separate small anomalies, like cities, which tend to be warmer than surrounding areas, cooler high elevation area, and areas near mitigating large bodies of water, into their proper zones.
  • It’s the first map designed to be viewed via the internet. Zones can be zoomed in on a finer scale.
  • A more sophisticated algorithm was used to compile low-temperature values from actual weather reporting stations.
  • The zones are based on 1976–2005 weather data. The 30-year period was chosen as a means to factor in year-to-year fluctuations and variations. They did a trial check on more recent data and it did not make a measurable difference in zones. (The previous map was based on 1974–1986 data.)

Climate Change Conclusions: Climate changes are usually based on weather averages in a 50- to 100-year period. This map uses only a 30-year average and is not meant as evidence of temperature changes. While most zones are ½ zone warmer than the previous map, the change can in part be attributed to better mapping and weather tracking. The USDA points out that some mountainous regions that had been hard to observe are now in cooler zones.

Interactive Map: There’s an interactive map that allows you to enter your zip code or click on the map and get your zone, actual average temperature, the temperature range for your zone, and your longitude and latitude.

How to Plant Double Bloom Hibiscus

Double bloom hibiscus is part of the tropical hibiscus family. The bloom has five base petals, the same as other single bloom hibiscus plants, but double bloom plants also have multiple petals that develop from the base of the bloom. Tropical hibiscus plants may be grown in the ground in Zones 9 and 10, but the ground around the plants should be kept warm through the cold season. Most growers plant double hibiscus in a container so they can move the plant indoors before the first frost.

Select a container to house your hibiscus plant. A 10- to 14-inch container will work well for your double bloom hibiscus. If you plan to place your hibiscus outdoors, consider a planter with wheels for easy navigation when it’s time to move it inside. Hibiscus do not like wet feet, so make sure that the container has good drainage.

Purchase a quality grade of potting soil for your hibiscus plant. They prefer a more acidic soil, so look for potting soils that are designed for tropical plants, such as cactus and palm, at your local garden supply. There is an online retailer specializing in hibiscus potting soil, at, but acidic soils designed for tropical plants that you can find locally will also work well for your hibiscus.

Place 6 to 8 inches of potting soil in the base of the container. Remove the double bloom hibiscus from the grower’s pot, and knead the roots at the base to free them. Place the plant inside the container so that the top of the root ball is an inch or so beneath the rim. Fill in around the sides with potting soil.

Add a thin layer of organic mulch around the top of the hibiscus plant to help retain moisture. Water the plant well.

Place the planter in a sunny location that’s also protected from wind. Water your hibiscus plant daily if the plant is outside during the summer but less often if the plant is indoors. Just make sure that the plant does not sit in a basin of water.

Bring your potted hibiscus inside before the first frost. Remember to remove any dead material before you bring it inside. It’s also a good idea to prune the branches back to within 4 or 5 inches of the main stem before bringing it in. After you prune and while your plant is still outdoors, hose it down thoroughly to remove any bugs and let it dry.


The Hibiscus

Although widely known as Hawaiian hibiscus, Hibiscus rosa-sinensis was probably native to Southern China and south-east Asia, then spread to the Pacific Islands long before Europeans reached that part of the world. Today it is very popular as an ornamental plant in most warm countries, and the original red flowered plant has undergone tremendous development. Hundreds of cultivars are now available, with double and semi-double flowers in all colours except true blues and purples.

Common name:

Hibiscus Botanic name: Hibiscus rosa-sinensis


An evergreen shrub. The height varies depending on the cultivar: dwarfs are less than 1.5m (5′), mediums are 2m-3m (6′-10′) and talls are over 3m (10’+). Flowers can be single, semi-double or double. They come in red, pink, orange, yellow and white, often with several colours in the one flower. The leaves are dark green and glossy, with a paler reverse. Variegated varieties are also available.

Hibiscus shown in our segment:

‘Alyrah Carol’ – yellow and red flower
‘Apple Blossom’ – single, rose pink flower with deeper centre
‘Dawn’ – tall grower, flower flesh pink with red centre
‘Erika Nicole’ – pink flower
‘Fifth Dimension’ – mauve/yellow petals
‘Helen Sanders’ – yellow/red flower
‘Inca Rose’ – yellow flower with pink centre
‘Lovely Rea’ – orange flower
‘Purple Majesty’ – red/purple with white spots
‘Rosalind’ – orange/yellow flower
‘Ruth Wilcox’ – tall grower, flower single, satin pink
‘Silver Memories’ – grey with white veins on petal
‘Sunshower’ – orange flower with yellow edges
‘Wilder’s White’ – very tall, pure white single flower with red style. (Note: this is actually not a variety of H. rosa-sinensis, but the species H. arnottianus, known and sold as ‘Wilder’s White’ in Australia. It is compatible in crossing with H. rosa-sinensis, and has produced many horticultural cultivars. It is also used as an understock for grafting, as it is hardy and disease resistant.)

Best climate:

H. rosa-sinensis does best in warm temperate and tropical climates. Some older varieties (such as ‘Apple Blossom’) are very hardy and will tolerate cooler conditions. In very cold areas try growing a deciduous species such as H. syriacus.


feature or specimen shrub
pot plant
hedge/privacy screen
cut flowers
tropical-style gardens

Good points:

brightly coloured flowers
flowers available in a wide range of colours
lush, green foliage
easy to grow


Hibiscus plants are attacked by hibiscus beetle (holes in flowers), metallic flea beetle (holes in leaves) and aphids (damage on buds and new shoots). However, many people prefer to put up with a little damage rather than using pesticides.


Hibiscus need full sun – a northerly aspect is ideal. The soil should be well-drained, with a neutral to slightly alkaline pH.
These plants hate to dry out, so water regularly. Apply a thick mulch, but do not let the mulch touch the stem.
Prune late September to October (when all danger of frost has passed) to shape the plant, remove old wood and encourage flowering.
These plants are heavy feeders. Apply complete fertiliser (rose or citrus food is suitable) after pruning and during the flowering season. Water well before and after fertilising.

Further information

Hibiscus are readily available at nurseries and garden centres. Expect to pay from $9 for 140mm (6″) pots, and $16 for 200mm (8″) pots.

Further reading

‘Palmer’s Hibiscus in Colour’ is a book of hibiscus pictures by Stanley J. Palmer. It’s published by Lancewood Publishing Australia, 1997, ISBN 0646290479. Recommended retail price $35. Available from Florilegium, 145 St Johns Road, Glebe, phone (02) 9571 8222.

Hibiscus plants are tropical beauties that will bring an exotic look to your garden. They are durable plants that can grow to be up to 15 feet in height, and the colorful blooms will attract hummingbirds and butterflies to your garden. Since hibiscus plants are tropical, they need a certain amount of care to ensure that they thrive in other environments.

My garden is filled with these breathtaking beauties, and I know that with the right care, a hibiscus plant will reward you greatly. They look amazing when they are planted together, but if you have a small gardening space, then you can grow a hibiscus plant and make it the focal point in your garden instead. Since these plants can be difficult to care for, let’s me give you a few tips to get started with.

How to Plant and Care for Hibiscus

Hibiscus does not take a lot of effort to care for; it simply needs to have certain conditions in order to thrive. Let’s take a look at a few suggestions for growing a healthy, happy hibiscus plant.

Type of Soil

Hibiscus likes to be planted in soil that is slightly acidic. If the soil in your garden is not acidic, you can attempt to increase the level by adding peat moss to your garden. When you plant the hibiscus, place them in the soil about two or three feet from each other; these plants may seem small now, but they will grow to be pretty large with time. In addition, do not plant these plants before the frost threat is over for the year to ensure that they survive the cold temperatures.

Watering Hibiscus

Hibiscus need moist soil to grow, but it also needs to be drained well. This is so that the roots are not sitting in a large amount of water, which can cause the roots to rot. If the plant is under-watered, then it is possible that the blooming process would stop, since this is a method to protect the roots of the plant. The best way to ensure that the plant will be getting adequate water is to use an irrigation system that will drain out any excess water.

Optimal Lighting

The best location for a hibiscus plant is a location that is going to get direct sunlight for five to six hours a day. They will grow in partial sunlight, but at the expense of the blooms being produced. For optimal growth, the plant needs to have full sun as much as possible.

Temperature Requirements

A hibiscus plant will flourish the most in temperatures that remain between 60 degrees Fahrenheit and 90 degrees Fahrenheit. Once the temperatures start coming close to the 32 degree Fahrenheit mark, the plants must remain indoors so that the cold weather does not cause damage to the plant.

Pruning Hibiscus

Hibiscus plants do not need to be pruned, but with that being said, the plant will love the additional attention. If you are going to prune a hibiscus plant to rejuvenate its look, it should be done in early spring. This will stimulate the budding process and help the plant thrive throughout the summer months. If you happen to prune your hibiscus plants late in the season, do not trim the branches too far back because it can hinder the blooming process.

Fertilizing Hibiscus

When you fertilize your hibiscus plant, it is a good idea to utilize liquid fertilizer to ensure that it can be dispersed through the soil evenly. You will want a fertilizer that is high in potassium because it’s great for the growth of hibiscus plants, but you also want to avoid phosphorus because it is a mineral that can kill the hibiscus plant, especially if the mineral is accumulating in the soil. A great way to encourage growth in the plant is to add compost bark or worm castings to the soil once a year or more.

Wintering Hibiscus

If the temperature where you live tends to drop below 32 degrees Fahrenheit over the winter, then you will need to take precautions to ensure that the hibiscus plant is safe. First, you need to bring the plant indoors to a location that stays above 50 degrees Fahrenheit. It will also need a steady supply of sunlight and fresh water, though the plant will require less during the winter.

Over the winter, you may notice that your plant’s leaves are turning yellow. This is a trait that will develop if you have been overwatering your hibiscus plants. They should be watered regularly throughout the season, but only when the soil is dry to the touch. Any more than that can mean that you are overwatering the plant, and the leaves will begin to turn. If the leaves begin to fall from the plant, it is likely that the hibiscus is entering into a dormant state which means that the hibiscus will require a cool damp location to remain in that state during the winter.

Growing Hibiscus in Containers

Many find that growing hibiscus in a container is easier than growing the plant directly in the garden. If you plant the hibiscus in a pot, you can move it easily to make sure that it gets the light that it requires to grow. In the winter, you can make sure that the temperature is warm enough for the plant to survive, and if it suddenly is below freezing outside, you can quickly move the hibiscus indoors. Make sure that the planter is a pot that drains well. In addition, stone pots tend to encourage hibiscus growth, which is preferred for hibiscus plants rather than using a clay pot that can make the soil alkaline over time.


Propagating a hibiscus plant begins with a hibiscus soft wood cutting. This is a branch of an existing plant that has not yet matured. The limb will still be a bit soft, so be careful when trimming it. The cuttings should be four to six inches in length, and it should still have leaves on the end of it. Place the cutting into some well draining soil to encourage it to take root. Cover the cutting to create a greenhouse effect for the young plant and keep the soil moist until the plant takes root. Using this method, a duplicate plant will form.

Propagating with a seed is also a possibility, though the conditions need to be just right for it to work in most situations. Use the tip of a pen to create a small hole to place the seeds in, then you can cover the holes and water the soil where the seeds have been planted. Seedlings should peek through the soil in about two to four weeks.

Common Problems That Hibiscus Plants Have

Hibiscus plants can have an issue with the leaves turning yellow. This is often caused by too much water being given to the plant during the winter months. If this occurs, simply reduce the amount of water that you give to the plant, especially if it is dormant. On extremely hot days, there is also a chance that the leaves of the plant could burn. Even though hibiscus is a tropical plant, you may need to move it to a shady location once in a while. Aphids, mites, and whiteflies can also cause issues for hibiscus plants, so if you notice an infestation, use mild dish soap to clean the leaves. Some gardeners have reported buds falling before blooming – in this article you can find some tips to prevent Hibiscus flowers from falling.

Hibiscus plants are beautiful flowering bushes that take a lot of care, but if you are looking for a tropical touch to add to your garden, you have found the perfect plant. The short bloom life of a hibiscus is nothing to concern yourself with; you will see fresh new blooms by morning. Simply enjoy the colorful blooms before they begin to wilt during the afternoon.


You might recognize hibiscus flowers from postcards titling tropical locations such as “Greetings from Florida!” or “Aloha from Hawaii!” And while hibiscus are definitely hardy, heat-loving flowers, there’s a little bit more you might not know about the large pink and red flowers.

Quick little history lesson: There are eight hibiscus species, and they’re considered to be ancestors of exotic hibiscus that were originally native to the tropical islands of Mauritius, Madagascar, Fiji, and Hawaii.These are known as tropical hibiscus and can be traced back to either China or India. It is also important to note that there are hardier cousins, the perennial hibiscus (hibiscus moscheutos, commonly known as rose mallow), that are North American native plants.

Because these bright blooms make lovely landscape additions, we wanted to give you the rundown on exactly how you can grow and care for hibiscus in your own yard.

What to Know When Growing Hibiscus

There are few things you will want to take into consideration if you decide to start growing hibiscus. Here are step-by-step instructions so you’ll be able to cultivate these iconic blooms right in your own backyard.

1. Find Your Garden Zone

It’s important to know your garden zone so that you can plant the best varieties that will thrive in your area. Perennial hibiscus do best in zones 5-9 (21 degrees F/-1 degrees C at coldest), but tropical hibiscus need warmer temperatures (flower best at 60-90 degrees F/16-32 degrees C). If you live in a hot climate, hibiscus foliage will stay green and lush year-round. The flowers might take a break, but you’ll still have the vibrant leaves. However, if you live in a colder climate, the plant could die down into the ground like other perennials do. In that case, this article says you’ll want to cut the plant to about six inches above the ground to encourage re-growth when the weather warms up again.

2. Plant Your Hibiscus

Depending on your garden zone, you’ll want to choose your hibiscus variety accordingly. As far as hardy perennial hibiscus go, you’ll want to choose your location carefully, as the plant does not transplant well. Pick a spot that receives full sun and has rich, well-draining soil.

3. Keep Moist In Summer, Dry-ish In Winter

Since these flowers have a history in tropical climates, they do love water. You may need to water daily for your flowers will to bloom in July and August. Mulch helps, too. Keep your hibiscus well-hydrated in the summertime with moist soil. You’ll likely need to water daily for your flowers will to bloom in July and August. Keep in mind that these flowers might not last very long, but there are always new ones sprouting! As winter rolls around, make sure the soil is not soggy, and to protect your plant from a late spring frost, add mulch.

4. Fertilize Well

Some plants do not enjoy too much fertilizer. Hibiscus, however, is not one of those plants. Perennial hibiscus is a heavy feeder, so feel free to feed your flowers fertilizer rich with potassium and/or phosphorus. The main key here is that you should only fertilize during the summer when the blooms are budding. Your hibiscus does not need fertilizer in the winter, and it can actually burn the roots if it sits in the soil while your plant is dormant.

5. Give Your Hibiscus Friends!

Once you’ve got your beautiful hibiscus growing, give her some friends.Other flowers that go well with hibiscus are somewhat dependent upon the colour of your hibiscus. After all, you want an array of shades! For example, low-maintenance perennials such as Geranium Rozanne are great additions for hibiscus that don’t share their blue-violet hue. Plus, you won’t have to worry much about caring for Rozanne and can focus more on your hibiscus.

Are you ready to start growing hibiscus? Gardening is easy even for beginners when you join Rozanne’s Inner Circle. She helps you plant a thriving garden no matter your experience level!

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