Smooththroat stoneseed (Lithospermum cobrense)

Also known as: Cobres Gromwell

The Smooththroat stoneseed is a hardy perennial distinguished by its bright yellow, tubular flowers and coarse, hairy leaves. It thrives in rocky or sandy terrains, showcasing strong adaptability to dry conditions. Its gray-green foliage and unique nutlet fruits enhance its appeal, drawing the interest of humans and a variety of pollinators such as bees and butterflies.

In This Article

Care Tips Water Sunlight Temperature Soil Fertilize Prune Propagation Repotting

Attributes of Smooththroat stoneseed

Lifespan

Perennial

Plant Height

30-60 cm

Spread

20-30 cm

Leaf Color

Green

Flower Size

1-2 cm

Flower Color

Blue to purple

Images of Smooththroat stoneseed

Quickly Identify Smooththroat stoneseed

Lithospermum cobrense can be identified by its narrow, lance-shaped leaves and its clusters of small, tubular blue to purple flowers. It also features rough, hairy stems that can help in its identification.

Scientific Classification of Smooththroat stoneseed

Phylum

Vascular plants

Class

Dicotyledons

Order

Boraginales

Family

Borage

Genus

Gromwells

Species

Smooththroat stoneseed

Planting and Growing of Smooththroat stoneseed

Care Difficulty

Hard

Watering Schedule

Every 2 days

Sunlight Requirements

Full sun

Sunshine Duration

6-8 hours

Ideal Temperature

60-75℉

Soil Type

Potting Mix, Peat Mix

Soil pH

6.5-7.5

Fertilizer Type

Balanced

Pruning Season

Spring, Summer

Pruning Area

Branches, Leaves

Pruning Frequency

2 times a year

Repotting Season

Spring

Pot Type

Plastic, Ceramic

How to Water Smooththroat stoneseed?

Lithospermum cobrense thrives best when the soil remains slightly moist. Water the plant with about 300ml until you notice the water seeping through the drainage holes. This ensures the roots receive adequate hydration without stagnation, promoting healthy growth.

What are the symptoms of an underwatered Smooththroat stoneseed? ›

What should I do if my Smooththroat stoneseed is not getting enough water? ›

What are the symptoms of an overwatered Smooththroat stoneseed? ›

How to save an overwatered Smooththroat stoneseed? ›

What Are the Sunlight Requirements for Smooththroat stoneseed?

Sunlight Requirements: Full sun, Partial sun

Duration of light: 4-8 hours of sunlight

Full sun and partial sun conditions are ideal for Lithospermum cobrense. This ensures the plant receives enough energy for photosynthesis, boosting growth, flower production, and overall vitality.

How much sunlight does Lithospermum cobrense need? ›

What are some solutions to provide ideal lighting? ›

What benefits come from ideal lighting for Lithospermum cobrense? ›

What Is the Ideal Temperature Range for Smooththroat stoneseed?

Ideal Temperature: 60 ~ 75℉

For optimal growth, Lithospermum cobrense thrives best in a temperature range of 60°F to 75°F. Maintaining these conditions ensures healthy foliage and vibrant blooms, providing the plant with necessary warmth without risking overheating or chilling.

What Soil is Best for Smooththroat stoneseed?

Soil type: Loam, Sandy loam

Soil PH: 6.5 ~ 7.5

Lithospermum cobrense thrives in soil that provides adequate moisture retention without becoming waterlogged. The plant's roots benefit greatly from loamy soil that can retain moisture, ensuring steady hydration. To maintain vibrant growth, Lithospermum cobrense requires soil rich in essential nutrients. Loam provides a balanced mix of sand, silt, and clay that holds nutrients well and supports healthy plant development. A key requirement for Lithospermum cobrense is good drainage to prevent root rot. Sandy loam soils offer excellent drainage properties, allowing excess water to escape and protecting the roots from decay.

How to Fertilize Smooththroat stoneseed?

Fertilizer type: Balanced

For Lithospermum cobrense, use liquid fertilizer diluted to half strength, approximately 1 teaspoon per gallon of water. For slow-release fertilizers, apply around 2-3 tablespoons per plant, depending on the plant size and soil fertility.

How to Prune Smooththroat stoneseed?

Pruning Time: Spring, Summer

Begin by removing any dead or damaged branches to improve overall plant health. Use sharp, clean pruning shears to make clean cuts just above a set of leaves or a node to stimulate new growth. To shape the plant, identify long or stray branches and cut them back to enhance the plant's desired contour. Balanced pruning ensures that the plant remains visually appealing and promotes bushier growth. More About Pruning Techniques→

How to Propagate Smooththroat stoneseed plant?

Propagate Time: Spring, Early spring

To propagate Lithospermum cobrense from seeds, begin by collecting fresh seeds from mature plants. Ensure that the seeds are dry and free from any debris or plant material before sowing.

When propagating through cuttings, select healthy, disease-free stems that are around 5-8 inches long. Cut just below a node to increase the chances of successful rooting.

For both seeds and cuttings, plant them in well-draining soil and water thoroughly. Maintain a consistent moisture level and provide indirect sunlight to encourage growth.

More About Propagating Techniques→

How to Repot Smooththroat stoneseed plant?

Repotting frequency: Every 2-3 years

Lithospermum cobrense sends clear signals when it's time to repot: roots emerging from the drainage holes, soil compacted and drained poorly, or a sluggish growth rate, indicating it's ready for a fresh start.

Select a pot that is one size larger than the current one, offering good drainage. This ensures the plant has enough space to grow and prevents waterlogging, promoting root health and vigorous growth.

Opt for a well-draining sandy soil mix, similar to its natural habitat. This choice helps prevent root rot by allowing excess water to escape, ensuring the roots are not sitting in soggy conditions.