Looking for a sustainable and cost-effective choice for your front beds? A great choice for regions like Southwest Ohio that have fluctuating temperatures throughout the seasons are tender perennials.
In this blog post, we'll delve into what tender perennials are, how they differ from other plant classifications, and the benefits of growing them.
We'll also explore which tender perennials are suitable for Zone 6 and provide practical tips to help these delicate beauties survive the winter and return the following year.
What Is a Tender Perennial?
In the broad world of horticulture, plants are categorized based on their lifecycle and ability to withstand cold temperatures. Tender perennials are plants that fall between hardy perennials and annuals in terms of their tolerance to temperature extremes. The term “tender” refers to their sensitivity to cold weather; they can’t tolerate freezing temperatures for prolonged periods and may not survive harsh winters.
Unlike true annuals, which die after one growing season regardless of temperature, tender perennials can survive for several years—if they are given the right conditions or winter protection.
The classic example is the geranium, which is often treated as an annual in cooler climates but can be kept for years in warmer zones or when brought indoors over the winter.
How Are Tender Perennials Different from Other Perennials?
A perennial is a plant that comes back for many years (at least more than 2!) Perennials grow and bloom during the spring and summer, go dormant in the fall and winter, and then return the following year from the same root system. This cycle can continue for many years, with some perennial plants living for decades.
Tender perennials differ from hardy perennials, which can survive extreme cold without much intervention. Hardy perennials are often native to colder climates and have adapted mechanisms—such as thicker roots, hardy stems, or chemical defenses—to survive through the coldest months.
Tender perennials, on the other hand, lack such cold-hardiness. Their root systems, stems, and leaves are more susceptible to damage from frost and freezing temperatures.
As a result, while hardy perennials will easily come back year after year in the same garden, tender perennials need some extra TLC to ensure their survival, especially in zones where temperatures dip below freezing, like right here in Southwest Ohio.
How Are Tender Perennials Different from Annuals?
Annuals are plants that complete their entire lifecycle—from seed to flower to seed again—in a single growing season. Once an annual’s growing season ends (typically at the first frost in cooler climates), the plant dies completely, root system and all. Common annuals include marigolds, zinnias, and impatiens.
Tender perennials, in contrast, have the potential to last multiple years. They die back when the weather turns cold but, given the right care or protection, they can regrow from the same rootstock in the spring.
This means that gardeners in cooler climates can sometimes keep their tender perennials alive year after year, treating them as a sort of cross between annuals and hardy perennials.
The Benefits of Planting Tender Perennials
Despite their need for extra care, tender perennials offer a range of benefits that can make them a worthwhile addition to the garden:
- Extended Blooming Period: Many tender perennials have an exceptionally long blooming period compared to true perennials, offering colorful displays from spring through to the first frost.
- Economic and Environmental Advantages: Because they have the potential to live for multiple years, tender perennials are a more sustainable choice than annuals, reducing the need for replanting each year and thus lowering the environmental impact.
- Versatility: Tender perennials are often used as annuals in cooler climates but can be overwintered indoors or in greenhouses. This flexibility means they can be used to fill out summer borders and then brought inside to be enjoyed as houseplants during the winter.
- Unique Foliage and Forms: Tender perennials often boast unique foliage and forms that may not be found among more hardy perennials. This makes them an excellent choice for adding texture, color, and interest to your garden beds.
Tender Perennials for Southwest Ohio (Garden Zone 6)
In Southwest Ohio, which falls within USDA Hardiness Zone 6, winter temperatures can drop as low as -10°F to 0°F (-23°C to -18°C). These conditions are challenging for many tender perennials, yet several species can still thrive if given proper care. Some of the best tender perennials for this region include:
- Chrysanthemums (Mums): While often grown as annuals, chrysanthemums can be overwintered successfully in Zone 6 with proper care, such as mulching and selecting hardy varieties.
- Geraniums (Pelargonium): A classic garden staple, geraniums can be brought inside for the winter or grown in containers that are moved to a protected location when temperatures drop.
- Dahlias: With their bold blooms and variety of forms, dahlias can be dug up and stored over the winter, allowing gardeners to enjoy their beauty year after year.
- Lantana: Incredibly heat tolerant, lantana can be overwintered indoors or grown as a perennial in sheltered microclimates in Zone 6.
- Cannas: Known for their large, tropical leaves, cannas can be dug up and stored over the winter or grown in pots that are brought indoors.
- Fuchsia: With its delicate, pendulous flowers, fuchsia adds vibrant color to shady spots. It can be overwintered as a houseplant in cooler zones.
- Lemon Verbena: This fragrant herb is often treated as an annual in Zone 6, but it can be brought indoors or heavily mulched to survive the winter.
We offer all these plants (and much more!) at Stockslagers Greenhouse and Garden Center in New Lebanon, Ohio, just west of Dayton. Stop on by to explore our wide selection of locally-grown plants, and be sure to ask our gardening experts any questions you may have!
Ensuring Your Tender Perennials Come Back Next Year
The key to enjoying tender perennials year after year lies in understanding their needs and providing appropriate winter protection. Here are some strategies to help your tender perennials survive and thrive through the winter months:
1. Mulching
Mulching is one of the easiest and most effective ways to protect tender perennials. Apply a thick layer of mulch (3-4 inches) around the base of your plants in late fall, once the ground begins to cool but before it freezes. Mulch acts as an insulator, protecting roots from freezing temperatures and preventing the soil from experiencing drastic temperature fluctuations.
2. Lifting and Storing
For certain tender perennials like dahlias and cannas, lifting and storing the tubers or bulbs is the best way to ensure survival through the winter. Carefully dig up the plants after the first frost, remove excess soil, and allow the tubers or bulbs to dry for a few days. Then store them in a cool, dry location (like a basement) in boxes filled with peat moss or sawdust to prevent them from drying out.
3. Overwintering Indoors
Some tender perennials, such as geraniums, lantana, and fuchsia, can be brought indoors and grown as houseplants during the winter. Place them in a sunny location and reduce watering to match the lower light levels.
4. Choosing Hardy Varieties
Not all varieties of tender perennials are created equal. For example, when planting chrysanthemums, choose varieties that are labeled as hardy for your zone. These types are more likely to survive cold temperatures with minimal intervention.
5. Using Microclimates to Your Advantage
Plant tender perennials in locations that offer some natural protection from the cold, such as near a south-facing wall, where the plants can benefit from the radiant heat. This can make a significant difference in borderline hardiness zones like Zone 6.
Special Consideration: Overwintering Mums in Zone 6
Mums, or chrysanthemums, are a quintessential fall plant, but many gardeners treat them as annuals, discarding them after one season. However, with a little extra care, you can keep your mums coming back year after year.
- Planting Timing: To increase the likelihood of your mums returning in the spring, plant them in the ground in early fall rather than late fall. This gives them time to establish their root systems before the ground freezes.
- Choosing Hardy Mums: Not all mums are equally hardy. Look for varieties specifically bred for cold tolerance, such as those from the Mammoth or Igloo series.
- Mulching and Pruning: After the first hard frost, cut back your mums to about 3 inches above the ground. Then cover them with a thick layer of mulch to insulate the roots and crown.
- Avoid Overwatering: Mums don’t like soggy soil, especially during the winter months when they are dormant. Ensure your planting site has well-draining soil to prevent root rot.
Final Thoughts
Tender perennials may require a bit more effort to maintain than hardy perennials, but they reward gardeners with vibrant blooms and lush foliage year after year. With thoughtful care, these versatile plants can become long-lasting staples in your Zone 6 garden, offering both beauty and sustainability. Whether you’re looking to experiment with new plant varieties or maximize your garden’s impact, tender perennials are a worthy addition that can thrive for seasons to come.
