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Zone 4 Yucca Plants – What Are Some Winter Hardy Yuccas

Zone 4 Yucca Plants – What Are Some Winter Hardy Yuccas


By: Bonnie L. Grant, Certified Urban Agriculturist

Adding a touch of desert elegance to the northern or cold season garden can be challenging. Lucky for those of us in cold zones, there are winter hardy yuccas which can withstand temperatures of -20 to -30 degrees Fahrenheit (-28 to -34 C.). These are zone 4 average cold temperatures and require one of the cold hardy yucca varieties if you wish your plant to survive winter. This article will detail some of the zone 4 yucca plants suitable for such chilly climes.

Growing Yuccas in Zone 4

Southwestern plants are appealing due to their diversity and adaptability. Yuccas are primarily found in the tropical to subtropical Americas and tend to prefer warm, dry regions. However, there are some cold hardy yucca varieties which are suitable for extreme cold temperatures.

In fact, even though we associate these relatives of Agave with desert heat and dryness, some forms have been found growing in the crisp region of the Rocky Mountains in winter. You just need to make sure you choose an appropriate variety with cold tolerance and adaptability to freezing temperatures.

Simply selecting cold hardy specimens is no guarantee they will thrive in such extreme weather conditions. Heavy snow can damage foliage and deep freezes that are longer than a week can adversely affect roots of shallowly planted yucca. Some tips can help successfully grow yuccas in zone 4.

  • Planting your yucca in a microclimate in your garden can help protect the plant from some of the cold temperatures.
  • Using a southern-facing wall or fence can help reflect winter sun and produce a moderately warmer region. It also reduces the plant’s exposure to cold northerly winds.
  • Do not water plants before a hard freeze, as excess moisture in the soil can turn into ice and damage the roots and crown.

In extreme cases, growing yuccas in zone 4 may require more obvious protective steps. Use organic mulch around the root zone in a layer of up to 3 inches (7.6 cm.) and protect plants in exposed situations by placing plastic over the entire plant during the night. Remove it during the day so moisture can escape and the plant can respirate.

Zone 4 Yucca Plants

Some yuccas can grow into trees, such as the Joshua tree, while others retain a tidy, low rosette perfect for containers, borders and accent plants. The smaller forms are usually hardy in areas with consistent snow and freezing temperatures.

  • Yucca glauca, or small soapweed, is one of the best winter hardy yuccas and has lovely narrow bluish green leaves. The plant is hardy in much of the Midwestern United States and can withstand temperatures of -30 to -35 Fahrenheit (-34 to -37 C.).
  • The tidy little 2-foot (61 cm.) tall Yucca harrimaniae, or Spanish bayonet, has very sharp leaves as the name suggests. It is drought tolerant and thrives in cold winter regions.
  • The dwarf yucca, Yucca nana, seems made for container growing. It is a neat little plant of only 8 to 10 inches (20 to 25 cm.) in height.
  • Adam’s needle is a classic cold hardy yucca. There are several cultivars of this zone 4 plant, Yucca filimentosa. ‘Bright Edge’ has gold margins, while ‘Color Guard’ has a central cream stripe. Each plant approaches 3 to 5 feet (.9 to 1.5 m.) in height. ‘Golden Sword’ may or may not be in the same species depending upon who you consult. It is a 5- to 6-foot (1.5 to 1.8 m.) tall plant with narrow leaves sliced through the center with a yellow stripe. These yuccas all produce flower stalks decorated with creamy bell-shaped flowers.
  • Yucca baccata is another cold hardy example. Also known as banana or Datil yucca, it can survive temperatures of -20 degrees Fahrenheit (-28 C.) and possibly colder with some protection. Plants have blue to green leaves and may produce thick trunks.

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Temperatures in Zone 4

USDA hardiness zones help farmers, gardeners, and agriculturalists, in general, to know which plants are suitable to grow at what times of the year. The USA is divided into 13 zones, and each zone is further divided into two subsets, a and b. While each zone is about 10 degrees Fahrenheit less than the zone above it, the subsets are a way to finesse this categorization.

So absent cold fronts or freezing storms, people living in zone 4b will experience temperature about 5 degrees Fahrenheit higher than those living in zone 4a. If you’re a gardener in hardiness zone 4, you should find out the subset you belong to and base your planting schedules on the average minimum temperature.

Zone 4 usually gets a minimum temperature between -20 degrees F to -30 degrees F in the winter. However, subset zone 4a, for example, is expected to get between -25 degrees to -30 degrees F, which is about 5 degrees warmer than 4b, which averages between -20 degrees to -25 degrees F annually. Keep in mind that the temperature could drop further as a result of unexpected weather events.


Tips on Growing Cold Hardy Tropical Plants

Most of the cold hardy tropical plants featured here do not require much specialized care. But it helps to be prepared and to do your research before buying.

1. Read the Label

Like all plants, cold hardy tropical plants have specific light, water and soil needs. Do your research, beyond just checking your USDA Growing Zones, to make sure you can provide for your new plant’s needs.

Most of the cold hardy tropical plants mentioned here can withstand very cold temperatures. But they require high humidity and consistent moisture to thrive.

(Sorry, desert gardeners. You’ll have the best success growing these plants in a humid indoor environment. So, grow tropical plants in a greenhouse. Read Backyard Greenhouses for Every Budget for more info.)

2. Mulch, Mulch, Mulch

Mulching is always a good idea. For tender tropical-looking plants, it’s a 100% requirement. Do not skimp on mulch! Mulch will keep weeds down and make your garden beds pretty. It also insulates your plants’ roots against hot and cold temperatures, and it is vital for retaining moisture in the soil.

3. Water Properly

With a few exceptions, such as the Toad Lily, most plants prefer to be watered deeply. After watering, allow them to dry out a bit before you water them again. Rather than taking the “little and often” approach, water thoroughly—but only when your plant needs it.

4. Fertilize

Cold-hard tropical plants, like their cousins that grow in actual tropical climates, benefit from the right plant fertilizers. Not all plants are the same, and not all plants need the same nutrients in the same amounts. Here are some good fertilizers for specific types of plants.

Dr. Earth Exotic Blend Fertilizer

Non-GMO organic fertilizer for palm, tropical and hibiscus plants. Handcrafted from human and feed grade ingredients, and enriched with multi-minerals. No synthetic ingredients. A very highly rated fertilizer. Check price on Amazon .

Grow More Hawaiian Bud & Bloom Fertilizer

A high-quality water-soluble concentrated fertilizer that contains no urea. Considered a top bloom formula in commercial agriculture, and an excellent fertilizer for virtually all flowering plants. Can be used in soil and foliar applications. Check price on Amazon .

Jobe’s Organic Fruit & Citrus Fertilizer

A fast-acting, organic granular fertilizer for fruit and citrus trees. OMRI listed for organic gardening by USDA. (Certified organic means no synthetic chemicals.) Improves soil conditions, and helps trees resist disease, insects,and drought. Check price on Amazon .

Nelson Plumeria and Flowering Tropicals Food

Balanced ingredients to encourage flower blooms. Higher phosphorus content produces more blooms, while sulfur helps increase soil acidity (which tropical plants love). Can be used for flowering trees, shrubs, tree ferns, orchids, plumeria and more. Check price on Amazon .

5. Winterize

The success of growing tender plants (like the hardy banana) at the edge of their growing zone comes down to winterizing properly. In Zones 5 and 6, for example, you will need to cut your banana to the ground and mulch it with a pile of straw for extra protection from the cold.

Other plants, such as the fig tree, may also need to be brought into a shed or garage to sit out the winter cold. Do your research on proper winterizing before you bring a cold hardy tropical plant home. This is especially true if your garden is at the colder edge of its growing zone.

Growing cold hardy tropical plants is an exhilarating experience. Plants like the hardy banana and canna lily are proof that almost everyone can grow a garden with a tropical look and feel. Try a few of these cold hardy tropical plants yourself for a fun and unique garden experience. Happy growing!


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Yuccas for Texas High Plains Landscapes

There are many yuccas we can grow in the Texas Panhandle that are all low water-use. Those yuccas native to the southeastern United States can take medium water, while those native to the southwestern areas are quite drought tolerant. Soils for all these yuccas should have fairly good drainage. Avoiding overwatering in clay soil.

As with most native southwestern plants, for decades it was assumed the cold hardiness of yucca were fairly warm blooded. However, these early cold hardiness ratings were issued by gardeners and botanic gardens from more moist winter climates. In soil with good drainage, less organic matter and our normal winter moisture, yucca are hardier than first thought.

The temperatures given below are all conservative. With good soil drainage they can winter over very nicely for us, many in a Zone 6 winter (down to -10°). Some of the yuccas are stemless, others single trunked or multiple trunked, most forming multiple clusters.

Roots of yuccas grow deep propagation is by root divisions with the trunkless yuccas, as they are clump forming. Try to dig out as deep a section of root as possible, then nurse its growth along for a year before letting it on its own. I've not attempted propagation of the trunk forming yuccas.

Much of this information is taken from Mary and Gary Irish's book, Agaves, Yuccas and Related Plants, and from my own experience with them. For much more information on individual yucca species, click on Plant Lists, Yucca.

*Yucca aloifolia, Aloe yucca, SE native, different varieties including variegated, single stemmed or simple branched, cold hardy to 0°.

*Y. baccata, banana yucca, SW, small trunked, to -20°.

Y. brevifolia, Joshua Tree, largest yucca tree-form up to 30 feet or more, Mojave Desert, -10°.

Y. elata, soaptree yucca, 1- 10 trunks up to 6-15' tall, SW, state flower of New Mexico, -10°.

Y. faxoniana, Faxon's yucca, SW, 6-20', usually 1 trunk but up to 6' tall, 0°.

*Y. filamentosa, SE, many varieties including 'Color Guard','Gold Sword', 'Bright Lights', 'Blue Sword', ''Hairy”, up to about 3 ft., trunkless, -20°. I've grown all but the 'Blue Sword' variety. Needs medium water-use, benefits from afternoon shade (leaves are thinner).

Y. flaccida, SE, small, stemless up to 3 ft., -20°.

Y. glauca, (aka Y. angustifolia) soapweed yucca, our area native grows as far north as Canada, mostly stemless, -35°. I haven't grown it!

*Y. harrimaniae, Harriman's yucca, SW, very small, usually not more than 12 inches, to -20°.

*Y. pallida, native to blackland prairies of Texas, clumping, stemless with blue leaves, to 0°. I've grown them for about 8+ years.

*Y. recurvifolia, (aka Y. pendula) SE and Gulf Coast Plains, medium to tall, can have multiple trunks, 'Yellow Ribbons' is a new variety, to 0°.

*Y. rigida, SW, blue yucca, medium sized, single trunked with multiple stems to 15', to 5° (Zone 7b). I've grown it for 5+ years.

*Y. rostrata, beaked yucca, similar to Y. rigida but with narrower leaves, single trunked with multiple stems, blue leaves, very attractive, to 5° (Zone 7b), thriving at Amarillo Botanical Gardens since 2006.

*Y. rupicola, twisted leaf yucca, stemless, clumping, bright olive green leaves, native to the Edwards Plateau only, to 0°. Wintered over reliably for 6+ years.

*Y. schidigera, Mohave yucca, SW, single trunk or clustered multiple trunks, to 0°.

*Y. schottii, mountain yucca, medium single trunked to 6-15', SW, to -10°.

*Y. smalliana, (aka Y. filamentosa var smalliana), small up to 8-10 inches tall, variegated, from 0° to -10°.

*Y. thompsoniana, (aka Y. rostrata), SW, treelike, temperatures down to 0° to -10°.

Y. torreyi, Torrey yucca, treelike up to 24', SW, to 5° (Zone 7b).

Y. whipplei, Chaparral yucca, single rosette or clumps to 3-6', SW, to 0°.

*I have grown the yuccas noted with an asterisk in my landscape or in other landscapes I've designed. Yucca's can make good container plants for temperature sensitive species.

Use in Garden

Yuccas are one of the plant genera that are what I term, southwest evergreens -- plants that provide that evergreen presence in our gardens. Sunny drought tolerant beds and borders. Native plant gardens. Rock garden (depending on species). Habitat garden. Southern garden. Xeric garden. The arborescent (tree-like) yuccas can be used as accent plants and focal points in the landscape. Yuccas work great in containers, whether they are cold hardy or non-cold hardy. Just be sure to move the containers inside during the winter.

Maintenance

Very little maintenance is needed. Cut off flower stalk in autumn or late winter.


Types of Yucca Plant

  • Yucca baccata. Also known as the Banana Yucca due to the shape of its fruits these can be eaten and baked like a sweet potato. “Datil yucca” is the other term for this variant in some locations, as the plant has some resemblance to an Agave. It has shorter trunk and bluer or more glacous folialge compared to other yuccas such as the Mojave yucca. It grows five feet and up in dry soil and full sun. Purple and off-white flowers will start to appear from mid-April to July.
  • Yucca carnerosana (Yucca faxoniana). This variety can grow 12 feet tall by six feet wide and is native in Mexico and Texas. It grows in part shade and full sun in zones 8a to 11, although gardeners from zone 6 particularly in Denver, CO are reported to be growing yucca successfully. They produce white flowers that will turn into a pretty shade of pink in mid to late spring when the plant blooms.
  • Yucca glauca. Produces grey to green leaves that form two foot mounds across the dry South-western part of the United States. This variety requires a dry climate and sandy soil in order to bloom. Flower stalks shoot will start to appear in early summer from the plant’s crown. Each stalk can produce up to 15 aromatic, greenish white flowers. The crown of the plant will die after blooming.
  • Yucca pallida. This variety is alternatively referred to as pale yucca due to its grey-green or blue-green leaves that form a rosette one or two inches tall. It is natively grown in Texas. Pale-leaf yucca can tolerate partial shade and full sun and its white flowers will start to appear in mid-summer these are held on upright stalks a couple of inches from the leaf tips.

  • Yucca rigida. A beautiful yucca palm that is also called as Blue yucca or Palmilla due to its striking blue-gray leaves these go well with its creamy yellow flower clusters. It is known to be enduring of zones eight to ten, and has also been reported as surviving the Phoenix, Arizona winters. The branching canes of Yucca rigida can grow up to 15 feet tall and six feet wide.
  • Yucca rostrata. Another type of beautiful blue yucca, which is commonly called the Blue Beaked yucca plant. It can be grown in cold places even in zone 5, as has been recorded in New York State and is one of the most cold hardy amongst the Yucca species.
  • Yucca rupicola. Fascinating type of yucca as its leaves are unique from that of other yucca leaves. The leaves are dark green in colour strap shaped, two inches wide, and form rosettes not greater than two feet tall. It is also termed as the Twisted-leaf yucca due to the ability of its leaves to twist with age. Yucca rupicola features red or white edges as well as curly white hairs, which are yuccan fiber. It can grow in partial shade and full sunlight and is native in Texas.
  • Yucca schidigera. Also known as Mojave yucca, this is basically a yucca tree. One of its common names is Spanish Dagger because of the sharpness of the tips of its yellow-green leaves. Its heavy canes can reach around six to 12 inches when the plant matures and will produce white flowers with a purple tinge. Yucca schidigera should be planted well away from foot traffic. It is closely related with Yucca baccata, and hybridizes freely with it they both inhibit the same range. Yucca schidigera is native to the Sonoran and Mojave deserts of Arizona, Nevada and California.
  • Yucca gigantea (Synonyms: Yucca elephantipes and Y. guatemalensis). this is the tallest if the yuccas and can reach heights of thirty feet (9 M). It is commonly referred to as the Giant, Spineless, or Soft-tip Yucca. It blooms with white flowers in the summer. The Yucca elephantipes plants are drought-tolerant and often grown indoors as house-plants when they are young.

Some species, such as Yucca elephantipes, can have spreads of well over 6 m (about 20 feet). Photograph by Wallygrom.


Cold Hardy Herbs

Many herbs don’t seem to mind the cold, and will keep on growing right through snow and early frosts. We harvest chives into early December, months after the first frost. They’ll also pop up through the snow in the early spring, before the ground has even melted out. Other cold hardy herbs include:

  • Cilantro
  • Thyme
  • Sage
  • Lavender (leaves, not flowers)

Not surprisingly, with the exception of strawberries, the list of cold hardy vegetables has a heavy overlap with vegetables that grow in shade. That about covers all the winter crops we grow on our homestead, but I’d be interested to know if we missed any of your favorites. I’m always looking for new cold-hardy vegetable varieties.


Watch the video: Beware! The dangers of the Yucca plant.