Home » Grow Cardinal Flowers from Seed: Attract Hummingbirds

Grow Cardinal Flowers from Seed: Attract Hummingbirds

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Cardinal flowers (Lobelia cardinalis) are native North American perennials that not only bring vibrant color to your garden but also play a vital role in supporting local pollinators. If you’re excited about growing your own cardinal flowers from seed, you’re in the right place! In this comprehensive guide, we’ll cover everything you need to know, from collecting seeds to planting and caring for your beautiful blooms.


Key Takeaways

  • Cardinal flowers are native perennials with vibrant red blooms.
  • Collect seeds in late summer or early fall when pods are dry.
  • Seeds benefit from cold stratification and soaking before planting.
  • Surface sow seeds and provide light for germination.
  • Start seeds indoors for better success and transplant when seedlings are strong.
  • Maintain consistently moist soil and provide adequate light.
  • Cardinal flowers attract hummingbirds and butterflies.
  • Cardinal flowers can be grown in containers and are deer-resistant.

Cardinal Flower Basics

Botanical NameLobelia cardinalis
Germination time14 days
Seed planting depthSurface sow, needs light to germinate
BloomsLate spring through fall
AttractsHummingbirds, butterflies
DescriptionFeatures erect, terminal spikes of large, cardinal red flowers on unbranched, alternate-leaved stalks.

What are Cardinal Flowers?

These stunning red flowers, characterized by their tubular shape and intense color, can grow up to 4 feet tall and attract hummingbirds and butterflies. With their showy spikes of flowers, cardinal flowers can make a striking addition to any garden.

Ideal growing conditions

Cardinal flowers thrive in moist, fertile soil and prefer partial to full sun, making them perfect for planting along stream banks or in rain gardens. They’re also highly adaptable and can tolerate a range of conditions, so long as the soil remains consistently moist.

Collecting and Storing Cardinal Flower Seeds

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Growing cardinal flowers from seed is an exciting and rewarding process. To get started, you’ll need to collect and store the seeds properly, ensuring they remain viable for planting.

In this section, we’ll discuss when and how to collect seeds, as well as the best practices for storing them.

When to collect seeds

Collecting seeds at the right time is crucial to ensure their viability. Cardinal flower seeds should be harvested in late summer to early fall, as this is when seed pods have dried and turned brown.

To determine if the pods are ready, gently squeeze them to see if they easily break apart. If they do, it’s time to collect the seeds.

How to collect Cardinal Flower seeds


To collect seeds from your cardinal flowers, follow these simple steps:

  1. Choose a dry, sunny day for seed collection, as damp seeds can develop mold and may not germinate.
  2. Carefully remove the seed pods from the plant. Be sure not to disturb the seed pods.
  3. Place the seed pods in a paper bag, allowing them to dry for a few days in a well-ventilated area away from direct sunlight.
  4. Once the pods are completely dry, gently crush them between your fingers to release the seeds.
  5. Separate the seeds from the chaff by using a sieve or by gently blowing on them.

Storing seeds properly

Proper storage is essential for maintaining the viability of your cardinal flower seeds. Follow these guidelines to ensure they’re ready to plant when the time comes:

  1. Store the seeds in a cool, dark, and dry place, such as a basement or closet. Avoid areas with fluctuating temperatures or humidity, as this can reduce seed viability.
  2. Place the seeds in a sealed container, such as a glass jar or plastic bag, to protect them from moisture and pests. If possible, add a desiccant packet to the container can help absorb any excess moisture.
  3. Label the container with the seed type and date of collection, so you can keep track of their age and viability.
  4. Check the seeds periodically to ensure they remain dry and mold-free. Discard any seeds that show signs of damage or mold.

Preparing Seeds for Planting

Seed stratification

Cardinal flower seeds benefit from a period of cold stratification to break their dormancy and improve germination rates.

To do this, mix the seeds with moist sand or peat moss and place them in a plastic bag. Store the seeds in the refrigerator for 4-6 weeks, checking occasionally to ensure the medium remains moist.

Start Cardinal Flowers From Seed Indoors

The seeds and resulting sprouts are very tiny. Starting Cardinal Flowers from seed directly in the garden is challenging. Your best option is to start cardinal flowers from seed indoors.

By providing a controlled environment, you can carefully monitor seed germination and seedling growth, ensuring your young plants are healthy and strong before transplanting them outdoors.

Here’s a step-by-step guide on how to start cardinal flower seeds indoors:

Choose the right containers

Select containers with good drainage, such as seed starting trays or small pots with drainage holes. You can also use biodegradable containers, like peat pots or egg cartons, which can be planted directly into the soil to minimize root disturbance during transplanting.

Prepare the growing medium

Fill your containers with a high-quality, well-draining seed starting mix. A combination of peat moss, vermiculite, and perlite is ideal for providing the necessary aeration and moisture retention required for successful germination.

Stratify and soak the seeds

Stratify the seeds by mixing them with moist sand or peat moss and refrigerating them for 4-6 weeks.

After stratification, soak the seeds in water for 24 hours to soften the seed coat and encourage germination.

Sow the seeds

Surface sow the cardinal flower seeds onto the prepared seed-starting mix, lightly pressing them into the soil without covering them. Cardinal flower seeds need light to germinate, so make sure they remain exposed to light after planting.

Maintain proper moisture and temperature

Cover the containers with a humidity dome or plastic wrap to retain moisture and create a mini greenhouse environment.

Keep the soil consistently moist but not soggy, as overly wet conditions can lead to seed rot.

Place the containers in a warm location with a consistent temperature of 70-75°F to promote germination. Using a seedling heat mat will ensure a speedy germination time.

Provide adequate light

Place the seed trays or pots in a bright, sunny location or under artificial grow lights. Cardinal flower seeds require ample light for germination and healthy seedling growth, so ensure they receive at least 12-14 hours of light per day.

Monitor germination and seedling growth

Cardinal flower seeds typically germinate within 14-21 days. Once seedlings emerge, continue to provide consistent moisture and light.

If you don’t have a south facing window, be sure and use a seed starting grow light to ensure they receive enough intensity for proper growth.

Harden off seedlings

Before transplanting your seedlings outdoors, they need to be gradually acclimated to outdoor conditions. This process, called hardening off, involves exposing the seedlings to outdoor conditions for progressively longer periods over 7-10 days.

Start with a few hours of exposure to indirect sunlight and protected from strong winds, and gradually increase the duration and exposure to direct sunlight.

By starting your cardinal flower seeds indoors, you can give your plants a strong foundation for healthy growth and a successful blooming season. The extra effort and attention to detail will be well worth it when you see your stunning cardinal flowers thriving in your garden.

Transplanting and Growing Cardinal Flowers

When to transplant

Once seedlings have developed at least a few sets of true leaves, they are ready for transplanting outdoors. Waiting until this stage will ensure that the seedlings are strong enough to handle the stresses of transplanting.

Transplanting seedlings


Carefully transplant the seedlings to their final location, spacing them 18-24 inches apart to allow for proper growth and airflow. Gently loosen the root ball and place each seedling into a pre-dug hole, ensuring the soil level remains consistent with the original growing medium. Water the seedlings well to help settle the soil and reduce transplant shock.

Ongoing Care and Maintenance

Water the cardinal flowers regularly to keep the soil moist, and apply a balanced, slow-release fertilizer in early spring to promote vigorous growth. Monitor the plants for pests and diseases, and remove any dead or damaged foliage to maintain plant health.

As the flowers fade, you can deadhead the plants to encourage additional blooming, but remember to leave some seed pods intact if you wish to collect seeds for the following year.

Sharing Your Cardinal Flower Adventures

Growing cardinal flowers from seed can be a rewarding and enjoyable endeavor. With patience and proper care, you’ll be able to enjoy the vibrant beauty of these native perennials in your own garden.

We hope this comprehensive guide has provided you with the knowledge and confidence to get started on your cardinal flower journey.

As you embark on this gardening adventure, we encourage you to share your experiences, tips, and stories in the comment section below.

Your insights and anecdotes can help fellow gardeners on their own journey to grow stunning cardinal flowers from seed. Happy planting!

FAQ: Growing Cardinal Flowers from Seed

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Last updated on 2023-10-02 / Images from Amazon Product Advertising API

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8 thoughts on “Grow Cardinal Flowers from Seed: Attract Hummingbirds”

    1. I started mine over the winter under grow lights, around January. They sprouted quickly but are slow growers. By spring they were little rosettes of leaves only a 2-3 inches in diameter. I put them in the ground once threats of frost passed. Keep them well watered, Cardinal Flowers can tolerate moist soil and don’t like dry soil. They only grew foliage and got a fairly sizable base but never flowered the first year. The plants were likely just setting good roots the first season with not much action above ground. I think the foliage was only about 6-8″ in diameter by the end of the first season. This year (second season) they grew multiple big tall stalks of flowers from the base. Sometime soon I plan to make a post on updates (with pics) to show how the Cardinal Flowers I grew from seed are doing so check back. Hope this helps!

  1. Thank you for this update. I am getting ready to try germinating them for the first time. I am going to try the cell method and the tray and cross my fingers.

  2. I am following your instructions for planting Cardinal flower seeds. I used miracle grow potting soil, hopefully that works as well. I am wondering after you put it in the Ziploc bag do you spray the soil at all throughout the process?

    1. The soil did not require additional moisture or misting when in the Ziplock bag since it was sealed air tight. Before germination I only opened the bag daily, and just momentarily, to let some fresh air in. However, if you have them under a humidity dome that doesn’t fit tight, rather than a sealed bag, you may need to mist them.

      Cardinal flowers are pretty tolerant of moisture and commonly grow along ponds and such so don’t stress too much about overwatering as long as your soil drains well. Just don’t let the seeds sit in soggy soil.

      It was only after the seeds germinated and I removed them from the Ziplock, they required misting occasionally to keep the soil from drying out. Definitely use a spray bottle to gently moisten the soil. The seedlings will be very tiny and delicate for the first few weeks.

      Hope this helps!

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