Cold Hardy Cactus Part One Opuntia

Lots of people are interested in growing Cold Hardy Cactus. Many people are surprised to find out that Cold Hardy Cactus thrive and are native to many northern states such as Ohio, Michigan and Indiana and parts of Canada. Besides ornamentation Cactus fruits are harvested for human consumption and the stems are also used for many dishes. There are a number of genuses in the Cactus family that have representatives that are cold hardy in USDA Zone 6 and even colder climates. One of the larger genuses is Opuntia. I will cover several species of this genus in this blog post.

Opuntia_phaeacantha
Opuntia phaeacantha

The first species I will cover is Opuntia phaeacantha commonly called the Tulip Prickly Pear. It is native to northern Mexico the US Southwest, the Rocky Mountains as far north as Colorado and the Great Plains as far north as South Dakota. From its natural distribution it could be inferred that this species is hardy to at least USDA Zone 5 and possibly 4B. It has yellow flowers with red centers but the flowers can be pinkish or reddish in color as well. It blooms from spring through early summer. The fruit is edible and is red or purple in color. The whole plant including the fruits are covered with little spikes which can break off and get into the skin. The plant is shrubby and can form thickets in its native habitat. It can grow from 1′ to a little over 3′ in height. It can tolerate a variety of soil acidity and prefers a well-drained course soil. Sandy Loam is a good mix for this plant. It prefers full to partial sun.

Here is a link if you wish to purchase this plant from Amazon. Please be aware that I  receive a small commission if you make a purchase which helps support the costs of running this website.

(Opuntia_polyacantha
(Opuntia polyacantha

Opuntia polyacantha commonly called the Plains or Panhandle Pricklypear. It is native from northern Mexico to Alberta Canada. The flowers are yellow to orangish. It blooms from late spring through early summer. It has dry fibrous fruits. The plant can form small thickets. Hardiness can vary based on where the plant originates. It is a good guess that this is a USDA Zone 5 or 4B Hardy plant. It usually is under a foot tall. It prefers full to partial sun. Like most cactus it prefers a sandy/gravelly soil.

Opuntia_humifusa
Opuntia humifusa

Opuntia humifusa commonly called Devils Tongue. This is a plant with a large native range. it is native from New Mexico to Florida and into parts of southern Canada. The flowers are usually a shade a yellow. It blooms in the late spring. It has red edible fruits. It can form large clumps over time. It can range from just a few inches above the ground to close to 2 feet high. This plant appears by its range to be hardy to USDA Zone 4B. It prefers full to partial sun. Like most cactus it prefers a sandy/gravelly soil.

Here is a link if you wish to purchase this plant from Amazon. Please be aware that I  receive a small commission if you make a purchase which helps support the costs of running this website.

Opuntia_fragilis
Opuntia fragilis

Opuntia fragilis commonly called Brittle Pricklypear. This plant is native from New Mexico to northern Alberta Canada. It is probably the hardiest cactus being able to comfortably survive in USDA Zone 4 and likely into Zone 3. It blooms from late spring into summer. It forms a low mat close to the ground and seldom gets more than 5 inches tall. It prefers full sun but tolerates a moderate amount of shade. Like most cactus it prefers a sandy/gravelly soil.

Opuntia macrorhiza this is another cactus commonly called the Plains or Panhandle Pricklypear it is also called Western Pricklypear. This plant is native from New Mexico to the northern Midwest. This is a very hardy cactus possibly into USDA Zone 3. The flowers are yellow. It blooms from the end of spring through midsummer. It has red edible fruits. It forms a low mat and usually will not get higher than a foot in height. It can spread quite a bit over time. It prefers full sun. Like most cactus it loves sandy soils/gravelly soils but it can tolerate a fair amount of clay as well as long as there is decent drainage.

Here is a link if you wish to purchase this plant from Amazon. Please be aware that I  receive a small commission if you make a purchase which helps support the costs of running this website.

Top Ten Subtropical Plants for a USDA Zone 6B Garden

Subtropical Beach Scene
Subtropical Beach Scene

Lots of people in cooler climates are envious of images of Myrtle Beach or Florida or the beaches of Southern California. Even being in cooler climates we can achieve a similar subtropical look with the right plants. I have  assembled a top ten list of Subtropical Plants to grow in USDA Zone 6B.

I have also provided links if you wish to purchase any plants from this list on Amazon. Please be aware that I  receive a small commission if you make a purchase which helps support the costs of running this website.

    1. Sabal minor also known as Dwarf Palmetto (‘McCurtain’ is probably the hardiest variety)

2. Magnolia grandiflora commonly called Southern Magnolia ( ‘Bracken’s Brown Beauty’ and ‘Edith Bogue’ are probably the hardiest varieties)

3. Musa basjoo also known as Hardy Banana or Japanese Banana

4. Phyllostachys nuda (Cold Hardy Bamboo)

5. Yucca filamentosa commonly called Adam’s Needle

6. Ilex opaca commonly called American Holly

7.Vinca minor commonly called Periwinkle or Creeping Myrtle

8.Mahonia aquifolium commonly called Oregon Grape Holly

9. Erica x darleyensis  commonly called Winter Blooming Heath or Heather

10. Colocasia Gigantea commonly called Giant Elephant Ear (This is a perennial that if mulched heavily has survived and thrived in Zone 6 areas.

Cold Hardy Heather

 

 

Hillside of Heather
Hillside of Heather

Cold Hardy Heather and Heaths can be an interesting addition to your garden. People think of the windswept highlands of Scotland when they think of Heather but there are actually many species of Heathers from different parts of the world. All heathers are part of the family Ericaceae. There is a genus Calluna with just one species Calluna vulgaris which is the common heather. There is also the genus Cassiope which has a small number of species in it. The vast majority of plants people think of as heather are in the genus Erica. This genus has hundreds of species in it. These species can vary greatly in cold hardiness. Heathers and Heaths are known for their small flowers that bloom at different times of the years for different species and their spiky evergreen foliage. Most Heathers and Heaths are low growing plants but some species can grow 6 feet high or more.

Closeup of Heather flowers.
Closeup of Heather flowers.

The Common Heather Calluna vulgaris is the lone member of the genus Calluna and is native to Europe and associated Atlantic Islands and Turkey. It usually grows from a little under one foot to a little under two feet in height but in some cases it can grow taller. It is a perennial shrub with small evergreen leaves and flowers from mid summer to late fall depending on the climate it is grown in. It prefers acidic soil and sunny conditions to moderate shade. This is the famous Heather of the British Isles and the windswept moors of Scotland. It normally grows from less than one foot tall to around three feet tall. In some exceptional cases it can get taller. It is a frequent food for sheep and it also is managed in some cases by burns. The leaves are very small evergreen and scaly almost like conifer leaves. The flowers are usually a light pink but they can also be other colors.

Heather is a source of food for wildlife especially in the colder months. Besides decorative uses Heather has had various uses in the past and present. In the past it was used in gruit which was a mixture of herbs and spices used before the widespread introduction of hops to flavor beer. It was used in the past for thatching of roofs and stuffing mattresses. It was also used in medicine and continues today to be used in aromatherapy.

If you want to grow Common Heather it is generally considered hardy from USDA Zones 5-7 but it can be found growing in much colder Zones 3-4 in areas with persistent snow cover to protect it from the extreme cold of winter.

Here is a link if you wish to purchase this plant from Amazon. Please be aware that I  receive a small commission if you make a purchase which helps support the costs of running this website.

 

Heaths are close relatives of Common Heather but are in the genus Erica.

Erica Tetralix also called Cross Leafed Heath is native to western and central Europe like other Heathers and Heaths it requires a sandy soil. It is a small plant not growing much more than 20-50 cm in height depending on the cultivar. It has small scale like leaves and pink to white flowers. From my research it appears to be hardy to Zone 4.

Eric Carnea commonly known as Winter Heath or Winter Flowering Heather is native to higher elevations in central and southern Europe. It is hardy to Zone 5 and like all heaths and heathers likes a sandy acidic soil but it can tolerate more aklaline conditions than other heaths and heathers.. it is a small plant growing 4-12 inches tall. It flowers very early in the late winter or early spring. The flowers usually are pink or close in color but can be other colors. There are many different cultivars of this plant and it is widely planted.

Here is a link if you wish to purchase this plant from Amazon. Please be aware that I  receive a small commission if you make a purchase which helps support the costs of running this website.

 

Erica terminalis is also called Corsican Heath. It is native to the Western Mediterranean region It can grow up to six feet in height and not quite as wide. It has pink flowers in the summer and fall and can get some fall/winter color in the leaves. I have seen listings anywhere from Zone 5A to  Zone 7A for this plant. This is probably a Zone 7A-6B  Shrub but it might be possible to grow it in 6A or 5B with favorable conditions or a little bit of winter protection.

Erica spiculifolia also called Balkan Heath is another Heath to check out. In researching this plant I have read widely varying claims of cold hardiness everywhere from zone 7 to zone 3. It blooms early in the season with pink flowers. Sometimes it will bloom again in the fall. 20-50 cm in height. It is native to South Eastern Europe. I would guess that this is a solid Zone 5 plant.

Erica x darleyensis is a hybrid of Erica carnea and Erica erigena. It is a vigorous spreading plant with pink flowers that can flower from early fall through spring. There are many cultivars with different growth habits and it can vary from 8″to 20″ inches in height. From my research this appears to be a Zone 6 plant.

Here is a link if you wish to purchase this plant from Amazon. Please be aware that I  receive a small commission if you make a purchase which helps support the costs of running this website.

 

Heathers and Heaths can have a place in the Cold Hardy Tropical Garden. They are evergreen and some species flower in the off-season even into the winter. Also they are good if you are going for a Mediterranean inspired look. They can be the low shrubs to go with the larger broad leafed evergreen shrubs/trees and palms. If you don’t have the right soil/drainage you may have more luck building a raised bed for these plants. An ideal soil mixture for Heathers/Heaths in a raised bed would be a sandy loam heavy on the sand with a compost and peat moss for acidity. Go light on any supplemental fertilizer as over fertilizing can hurt the plants.

Winter protection for Heathers/Heaths. If they can be protected from drying winds it can be a help. Some gardeners have had success with a loose mulch of pine needles/branches, hay or straw have had success. Whatever you use don’t allow the plants to get smothered that could cause damage and mold/rotting issues.

 

My Favorite Book on Cold Hardy Tropicals

Dr. David Francko has written an excellent book about growing warm climate plants in cooler areas titled “Palms Won’t Grow Here and Other Myths: Warm-Climate Plants for Cooler Areas”

This is actually my favorite book on Cold Hardy Tropicals.  I got to meet Dr. Francko a number of years ago when he gave me a tour of the Miami University Campus. I was considering at the time writing my graduate thesis on Cold Hardy Palm trees. The tour was very informative and it was inspiring seeing all the interesting plants growing in southern Ohio.

Getting to the book review itself I purchased this book when it was first published and have referenced it ever since. I think the title says it all for those of us interested in growing interesting tropical type plants. Palms Won’t Grow Here and other myths. Warm Climate Plants for Cooler Areas. 

The book goes through very thoroughly all the aspects of growing exotic plants in cooler climates. Chapter One begins with challenging the myths of “It won’t grow here” There is a primer on subtropical gardening including a short history of the topic including Victorian era England which had a strong interest in the subject. There is also a discussion on the effect that future climate change could have on gardening. This chapter also discusses the conventions that occur in the book.

Chapter 2 is a primer on north by south gardening. There is an explanation of why palms grow in Florida and a discussion of cold hardiness. Plant hardiness maps are discussed including the fact that zone maps change over time. The concept of Microclimates is explained in this chapter. In chapter three Microclimate based landscape design and planning is discussed. Chapter Four is about four season care of warm climate plants. Chapter Five discusses Cold Hardy Palms.  Chapter Six introduces Broadleaved Evergreen Trees and Shrubs.

Chapter Seven discusses warm climate deciduous trees and shrubs such as Crape Myrtle. Chapter Eight goes over other warm climate plants such as Bamboo, Banana’s and Yucca. At the end of the book is an appendix with additional information. The book is generously endowed with high quality color photographs as well as black and white photographs. Anyways I hope you like my review. This is my favorite book on Cold Hardy Tropicals and it doesn’t disappoint.

Here is a link if you wish to purchase this book from Amazon. Please be aware that I  receive a small commission if you make a purchase which helps support the costs of running this website.

Betrock’s Cold Hardy Palms

This is an excellent book for the cold hardy palm enthusiast. Betrock’s Cold Hardy Palms is one of the handful of books that is out there to help the adventurous palm grower. There is a list of 82 different palm species that are able to grow in Climates colder than USDA Hardiness Zone 10. Zone 10A has a minimum low temperature of 30-35 degrees Fahrenheit.

For reference in the Continental United States Zone 10 climates are found on the Atlantic coast only in south central Florida and south. The extreme southern coastal tip of Louisiana is Zone 10 and also the extreme southern tip of coastal Texas.Out west zone 10 is much more common. Portions of western Arizona from the center of the state south are zone 10. Much of Coastal California along with the southern low desert is in Zone 10 as well. The book also includes a list of minimum temperature exposures for 139 additional palms.

The book itself is 168 color pages including 286 color photographs. There is information on cold hardy palms that are drought tolerant. There is also good information about palms that are shade and salt tolerant. The salt tolerant part can be important as some locations with superior microclimates for growing palms tend to be near the ocean.Examples of such microclimates include Martha’s Vineyard/Nantucket/Cape Cod, New York City/Long island and the New Jersey Shore.Some of these coastal areas are zone 7B which has minimum winter temperatures of 5-10 Fahrenheit. In areas zoned 7B Trachycarpus fortunei, Rhapidophyllum hystrix, and Sabal minor have been grown outdoors successfully without any significant winter protection.

Other additional information in the book includes important subjects such as  palms which can be hazardous to people. In closing Betrock’s Cold Hardy Palms is a great book and it will be helpful to anyone interested in growing cold hardy palms in colder climates.

Here is a link if you wish to purchase this book from Amazon. Please be aware that I  receive a small commission if you make a purchase which helps support the costs of running this website.

 

USDA Hardiness Zone Map

2012 USDA Hardiness Zone Map_(USA)
2012 USDA Hardiness Zone Map_(USA)

There are several different climate zone map systems devised for the United States. The first and most commonly known climate system is the USDA Hardiness Zone Map. The first map was issued in 1960. It was revised in 1965. The next time a new map came out was in 1990. This map was based on more reporting stations and it and it divided the temperature zones into five-degree a/b zones for greater accuracy. This map identified some areas as colder than the previous map due to some extremely low temperatures in the intervening years. The latest map came out in 2012. This map takes into account the warmer temperatures of the previous 30 years. Many areas moved up by a half zone and urban heat islands are taken into account. Depending on where your weather reporting station is located you may be in a different subzone or even a different zone. The difference between an inner city garden near downtown and the weather station located on a open and windy airport 20 miles out in the country can be quite great.

The zones are color coded to be more visible. One interesting thing to notice is that the zones are not even east to west across the country. There are a number of reasons for this. Higher Elevations tend to have cooler temperatures and also areas near oceans and large bodies of water have more moderate temperatures. An extreme example is  some areas near Seattle Washington have a Zone 9 A Climate. This is the same zone as Jacksonville Florida. Remember though that the USDA Zones record the minimum temperature. Other factors such as moisture, hours of sunlight and summer heat are important as well.

The USDA has a great website http://planthardiness.ars.usda.gov/PHZMWeb/#  which explains the USDA Hardiness Zone Map and how to use it. You can search your zone by zip code. It’s a fun feature to play with. Where I live in Toledo Ohio the city is divided into zones 6A and 6B with areas closer to downtown and Lake Erie 6B and more western areas 6A.