Category: Plant Festival, Durham County

Discover Keystone Plants and Local Ecotypes at the Durham EMG Plant Sale

On By durhammastergardenersIn Plant Festival, Durham County, Uncategorized

by Lissa Lutz, NC State Extension Master GardenerSM volunteer of Durham County

Local Ecotypes and Keystone Genera. What are they and why do they matter? Where can I get them? The second question is easy to answer: Come to the Durham Master Gardener Plant Sale on April 11, 2026. Lissa Lutz, chair of the plant sale committee answers the first question.

Keystone Plants

Keystone plants are a sub category of native plants that are uniquely essential to the local food web. According to research by entomologist Dr. Doug Tallamy1, a small fraction of native plants (about 14%) support the vast majority (90%) of butterfly and moth species. Without these specific plants, many caterpillars cannot survive. This leads to a collapse in bird populations that rely on them for food. Without keystone plants, the ecosystem collapses because the food supply and habitat for pollinators is threatened. Three example of perennials that are considered to be Keystone plants in our region are: Goldenrod (Solidago); Sunflower (Helianthus) and Asters(Symphyotrichum).

Goldenrod (Solidago)

We will have several varieties of Solidagos at the plant sale: Solidago caesia; Solidago bicolor; Solidago erecta; and Solidago rugosa ‘Fireworks‘. Goldenrods are considered a keystone plant species in that they support numerous species of birds, butterflies, bees and other insects. Goldenrods tend to be deer resistant, and contrary to popular belief they do not cause hay fever. Of special interest is Solidago caesia. It, is unusual in that unlike most other goldenrods it is happiest in a woodland setting. Rarely growing taller than 2 feet, it spreads slowly and politely, offering showy yellow blooms along bluish stems from late summer through fall. Blue Stemmed Goldenrods in the sale were grown from seeds collected from plants growing along New Hope Creek in Orange County, making this plant a local ecotype (more about what that means in the next section).

A close-up of a green plant branch with vibrant yellow flowers, surrounded by blurred foliage in the background.
Close-up of yellow flowering plants with green leaves in sunlight.

Solidago caesia supports Wavy-lined Emerald (Synchlora aerata) larvae. Flowers are attractive to butterflies, bees, and other pollinators. Songbirds eat the seeds. (Image credit: Dan Mullen CC BY-NC-ND 4.0; Debbie Roos)

Sunflower (Helianthus)

The main attraction in the Heilianthus family will be Helianthus angustifolius (Swamp sunflower). This is a great plant for the back border of a pollinator garden. Why the back border? Because it often grows to 8 feet tall. It may need to be staked in late summer if it is planted in a windy area but it will give you cheerful daisy like blooms well into the fall.

It is visited by specialized bees as well as generalist bees (such as bumblebees and honey bees). It is a source of nectar for many butterflies during fall migration and serves as the larval host for the Silvery Checkerspot butterfly.

A cluster of vibrant yellow flowers in front of a decorative stone backdrop.

Helianthus angustifolius (Swamp sunflower) has multiple blooms that sway in the breeze and it attract a number of pollinators. It is also a favorite of song birds. (Image credit: J. Biochemistn CC BY-NC 2.0)

Asters(Symphyotrichum)

Do we have a variety of Asters for you! Symphyotrichum georgianum (Georgia Aster); Symphyotrichum laeve (Smooth Blue Aster); Symphyotrichum oblongifolium (Aromatic Aster); Symphyotrichum patens (Clasping or Late Aster) will all be there ready to go home with you. The flowers have a long bloom season lasting from late summer until the first frost. Native bees nest in the dead, hollow stems, so gardeners are encouraged to cut back dead stems to 12 to 24 inches and allow them to remain standing until they disintegrate. Read more about best practices for stem-nesting bees in this NC Extension publication.

A lush patch of light purple flowers surrounded by fallen leaves and green foliage, with trees in the background.
A close-up of a bee perched on a purple flower with spreading petals, surrounded by green stems and buds.
A cluster of purple asters blooming in a garden setting.

Asters are a diverse group of plants. Some like sun others like a bit of shade. The are a must in the pollinator garden providing nectar in the fall and a home in the winter. (Image credit: Andrea Laine CC BY-NC-40; Debbie Roos)

Local Ecotypes

Local ecotypes are native plants that have been grown under local conditions. Using locally sourced plants increases survival rates, promotes genetic diversity, and supports specialized local pollinators and wildlife. They are crucial for restoring, sustaining, and improving local biodiversity. In addition to the Blue Stemmed Goldenrod mentioned earlier there will be many other plants that are local ecotypes.

Chrysopsis mariana, or Maryland Golden aster, is an under-utilized, tough as nails native that has bright yellow daisy-like blooms on 1 to 2 foot plants in the fall. This 2018 NC Botanical Gardens Wildflower of the Year attracts bees, butterflies and other pollinators, and thrives in poor, sandy, well-drained soils, though it is quite adaptable. The plants can be short lived but will reseed readily. They are also deer resistant. Maryland Golden asters in the sale were grown from seeds collected from plants growing on a roadside in Orange County.

Penstemon laevigatus, or Eastern Smooth Beardtongue, is a lovely Piedmont native that is easy to grow in sun or part shade and a variety of soils. The evergreen basal rosettes produce 2 to 3 foot stems with pale purple blooms from May through July. Hummingbirds, bees and other pollinators visit the tubular flowers. Eastern Smooth Beardtongue is an excellent cut flower and is moderately deer resistant. Plants in the sale were grown from seeds collected from plants growing along a power line in Orange County.

A black insect with orange markings collecting nectar from a bright yellow flower.
Cluster of tall flowering plants with white blooms and green leaves in a garden setting.

Chrysopsis mariana, or Maryland Golden aster (l) and Penstemon laevigatus or Eastern Smooth Beardtongue (r) will be available for sale. They are both sourced from locally grown seeds which helps them to live a healthy life in your garden. (Image credit: Cathy DeWitt CC-BY-NC-ND 4.0; JC Raulston Aboretum, CC BY, 2.0)

Other Powerhouse Pollinator Plants that will be available include: Eupatorium (serotinum, hyssopifolium), Rudbeckia (triloba, fulgida); Amorpha fruticosa, Oenothera fruticosa, Parthenium integrifolium, Cunila origanoides, Rhexia virginica, and Lonicera sempervirens. According to National Wildlife Federation each of these species support 15 or more insect species.

This is only a partial list of the plants that will be available. We have an excellent collection of vegetables (tomatoes, peppers, eggplant, cucumbers,and lettuce) including many small varieties that can be easily grown by people living in apartments or houses with limited space. Herbs are a great way to spice up your kitchen and we will have several varieties of basil, ginger, rosemary and chives. There will also be several well-behaved non native plants and a selection of shrubs and trees grown by our exceptional propagation committee. You can find a full list of plants at: https://www.backyardtreasuresplantsale.org/.

While you visit the sale, don’t forget to stroll through our Durham County Extension Demonstration Garden and see many of the plants that are being sold. A previous blog post describes the recent changes and additions to the demo garden.

Promotional poster for the NC State Extension Master Gardener volunteer plant sale featuring event details, including the date, time, and location.

Notes: 1 Doug Tallamy is an entomologist, conservationist, and professor at the University of Delaware. His work has informed our understanding of the relationship between native plants and wildlife. He has written several books and these are available at his website: https://homegrownnationalpark.org/doug-tallamy/

Additional Reading and Resources

The National Wildlife Federation has developed a list of Keystone Plants by ecoregion: https://www.nwf.org/Native-Plant-Habitats/Plant-Native/Why-Native/Keystone-Plants-by-Ecoregion

The NC Wildlife Foundation has a list of perennials and annuals that are great pollinator plants for our state: https://ncwf.org/habitat/native-pollinator-plants/perennial-annual-flowers/#:~:text=Great%20Blue%20Lobelia,seed%20in%20ideal%20garden%20conditions.

The NC Audubon Society offers a variety of strategies for increasing the number and diversity of birds in our state: https://www.audubon.org/north-carolina.

If you are interested in having your garden certified as a wildlife certified habitat go tohttps://ncwf.org/our-work/garden-for-wildlife/certified-wildlife-habitat/

Shortlink: https://wp.me/p2nIr1-7j9

Starting Seeds Indoors using a Light Cart: A Science-Based Guide

On By durhammastergardenersIn light cart, Plant Festival, Durham County, Plant sale, seed starting, Uncategorized

Part 3 of 3 – Hardening Off and Transplanting into the Garden

by Marcia Kirinus, NC State Extension Master GardenerSM volunteer of Durham County

This article is part three of a three-part series on starting seeds indoors using a light cart. In Part One, we focused on lighting and environmental setup, building the foundation for strong, healthy growth. Find it here.

In Part Two, we covered watering, fertility, and pest management — the daily disciplines that produce healthy root systems and balanced seedlings. Find it here.

Now we arrive at the final step: moving plants from a protected indoor environment, where nearly everything is controlled, into the garden – where nature takes over.

If seedlings could talk, this is what they would say: “I’m ready – but don’t rush me.”

Rows of small potted herb plants, predominantly basil and oregano, with blue labels indicating names or types.

Basil, (Ocimum basilicum), seedlings beginning the hardening-off process in bright shade. Early exposure is brief and protected, allowing leaves and stems to adjust gradually to sun, wind, and fluctuating temperatures. (Image Credit: Marcia Kirinus)

On your light cart, you controlled light, moisture, airflow, and nutrition. In the garden, you enter into partnership with weather, soil microbes, insects, and natural variability. If you have built strong roots, managed moisture wisely, and avoided excess fertility, your seedlings are prepared.

Hardening Off – Why it matters

Seedlings grown indoors live sheltered lives. Water and nutrients arrive on schedule. Light is steady. Temperatures are moderate. There is no harsh wind or intense ultraviolet exposure. Then one spring afternoon, we carry them into full sun, fluctuating temperatures, drying winds, and real UV radiation.

Without preparation, that abrupt shift can cause leaf scorch, wilting, stalled growth, transplant shock, and lasting setbacks. Hardening off is not optional, it is a physiological transition. During hardening off, plants thicken their leaf cuticle, strengthen cell walls, and adjust stomatal function to regulate water loss under changing conditions. You are not simply “getting them used to it.” You are allowing them time to rebuild tissues for outdoor survival.

This takes days, not hours.

Hardening Off – How To Do It

Hardening off is the gradual introduction of seedlings to outdoor conditions over 7–10 days, depending on weather and crop type. The goal is progressive exposure, not endurance.

Days 1–2:
1–2 hours outdoors in bright shade, protected from wind.

Days 3–4:
3–4 hours outdoors. Introduce gentle morning sun.

Days 5–6:
Half day outdoors, increasing light gradually.

Days 7–10:
Full days outside. Bring plants inside if nighttime temperatures fall below crop tolerance or if strong winds or heavy rain are forecast.

Observe daily. Slight wilting is feedback. Leaf bleaching is a warning.

Close-up of green plant leaves showing signs of discoloration and stress.

Leaf bleaching on Capsicum annuum caused by direct sun exposure without proper hardening off. Rapid ultraviolet exposure damages indoor-grown tissue before it has time to adapt. (Image generated for educational purposes.)

The Role of Wind

Indoors, air is still. Outdoors, wind creates mechanical stress that stimulates stronger stems through thigmomorphogenesis. Moderate movement encourages thicker, sturdier growth. This is why gentle air circulation on a light cart – or lightly brushing seedlings when young, improves transplant success. It prepares plants before they ever leave the house.

Transplant Size – When Are They Ready?

Height alone does not determine readiness. Structure does. Look for seedlings with two to four sets of true leaves, sturdy upright stems, and well-developed roots that hold the soil together when gently removed from the tray. Leaves should be evenly dark green, with no signs of pests or disease. A plant that appears small but strong will consistently outperform one that is tall and leggy.

A hand holding a small plant with green leaves and visible roots in a soil block.
A person holding a small plant with a well-developed root system, covered in soil, in a greenhouse setting with other plants in the background.

Seedlings are ready for the garden when they have multiple sets of true leaves, sturdy stems, and a well-developed root system. Balanced structure signals readiness. (Image credit: Marcia Kirinus)

Timing the Move to the Garden

In Durham, NC (USDA Zone 8a), the average last spring frost falls around April 10 – but averages are not guarantees. Light frosts may occur later, especially in low-lying areas. Cool-season crops such as lettuce, brassicas, and snapdragons tolerate cold and can often be transplanted several weeks before the last frost, provided they have been properly hardened off.

Warm-season crops – tomatoes, peppers, zinnias, basil – require patience. Wait until nighttime temperatures remain consistently above 50°F and soil temperatures have warmed. Air may feel pleasant on a sunny day, but soil temperature lags behind. Roots respond to soil temperature.

If uncertain, delay warm-season planting by a week. In our region, transplants set into warm late-April soil frequently outperform those planted too early into cold ground. Microclimates matter. South-facing walls, raised beds, and protected urban spaces warm faster than open exposures. Know your yard before planting.

Transplanting into the Garden.

How you transplant matters as much as when.

  • Prepare the Soil
    • Loosen soil thoroughly, ensure good drainage, and incorporate compost if needed. If soil is dry, water the planting area before transplanting.
  • Choose the right time
    • Late afternoon or early evening is ideal, allowing plants to recover overnight before facing full sun. Avoid midday heat or high-wind conditions.
  • Handle Roots Gently
    • Well-watered seedlings release from trays more easily and experience less root disturbance.
    • Water before removal.
    • Support the root ball – never pull by the stem.
    • Keep roots shaded and moist until planted.
    • If roots are circling heavily, gently loosen them.
  • Plant at Proper Depth
    • Most crops should be planted at the same depth they grew indoors. Tomatoes are the exception and can be planted deeper to encourage adventitious rooting.
  • Water In Thoroughly
    • Water immediately after planting to eliminate air pockets and ensure firm soil-to-root contact. Even if soil feels moist, this step is essential for establishing roots in their new environment.
A person in green gardening boots and blue jeans is using a gardening fork to turn soil in a wooden raised garden bed, with a pile of organic matter nearby.
A hand holding a young lettuce plant with roots, ready to be planted in the soil.
A green watering can pouring water onto a small plant in rich brown soil.

Soil preparation, gentle handling and careful watering are the final steps in successful transplanting. Loosened soil promotes root expansion, planting to the right depth and watering at the base of the plant ensures strong soil-to-root contact. (Images Generated for Educational Purposes)

Extra Insurance: Row Covers, Cold Frames, Cloches, and Mulch

Even properly hardened seedlings benefit from temporary protection during early establishment. In Durham’s unpredictable spring weather, lightweight floating row cover offers insurance against late frosts, drying winds, temperature swings, and early insect pressure. Row covers moderate extremes rather than eliminating exposure. Remove covers once plants resume active growth and temperatures stabilize.

Rows of garden beds covered with white fabric for winter protection, blanketed in a layer of snow.
Close-up of frosted green leaves in a garden, showcasing intricate ice crystals on the surface.

Left: Lightweight row cover protects cool-season crops from wind, heavy rain, and fluctuating temperatures while slightly increasing warmth beneath the canopy. Right: When uncovered, Scabiosa atropurpurea appears frosted but remains healthy – gradual acclimation allows plants to tolerate short cold events. (Image credit: Marcia Kirinus)

Cold frames, cloches, and heavy mulch serve a similar purpose. Each buffers conditions while plants adjust to their new environment. Protection is not about eliminating stress. It is about moderating extremes while roots establish and tissues strengthen.

A small greenhouse with a clear plastic covering and aluminum frame, placed on a grassy area.
Five clear plastic gardening cloches placed on a frosty ground, surrounded by dried vegetation and fallen leaves.

Left: A simple cold frame allows controlled ventilation and incremental exposure to outdoor conditions. Right: Cloches protect individual plants as they settle into the garden.(Image credit: Marcia Kirinus)

Bringing it Full Circle

The techniques described throughout this three-part series – intentional lighting, disciplined watering, restrained fertilizing, gradual hardening off, and careful transplant timing – are the same practices we use to grow plants for the Durham Extension Master Gardener℠ Volunteer Plant Sale on April 11, 2026.

Every plant offered has been raised using these science-based methods to ensure strong root systems, balanced growth, and successful establishment in your garden. When you bring one home, you are starting with a seedling that has been prepared – Slow grown, not rushed.

Final Takeaway

Hardening off and transplanting are measured transitions. The goal is not speed; it is continuity. A well-grown seedling moved thoughtfully into appropriate soil does not struggle – it adapts. Once established, it quickly outpaces plants that were rushed or transplanted carelessly. The discipline practiced indoors – managing light, moisture, airflow, and fertility – now pays dividends in the garden. From light cart to soil, each step builds resilience.

Resources and Additional Information:

Past Blog Post: Starting Seeds Indoors with a Light Cart: A Science-Based Guide, Setting everything up. (Part 1 of 3) https://wp.me/p2nIr1-6UX

Past Blog Post: Starting Seeds Indoors using a Light Cart: A Science Based Guide, water, fertilizer, pest control (Part 2 of 3) https://wp.me/p2nIr1-73H

Past Blog Post: What I love about starting seeds using a soil block: https://wp.me/p2nIr1-4rv

How to build your own raised bed cloche: University of Oregon: https://extension.oregonstate.edu/catalog/ec-1627-how-build-your-own-raised-bed-cloche?reference=catalog

Extending the growing season: start early, end later: University of Minnesota, https://durhammastergardeners.com/wp-admin/post.php?post=27417&action=edit

North Carolina Extension Gardener Handbook, Appendix E. Season Extenders and Greenhouses, https://content.ces.ncsu.edu/extension-gardener-handbook/appendix-e-season-extenders-and-greenhouses

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