Gratiola viscidula - Tissue Culture

Short's Hedgehyssop: The Spiky Midground Cushion

Short's Hedgehyssop (Gratiola viscidula), also known simply as Viscid Hedgehyssop or Hedge Hyssop, is a unique and relatively new tissue culture to the freshwater aquascaping hobby. This North American native perennial wildflower is highly adaptable and can be grown submerged in an aquarium or emerged in a paludarium or terrarium.

Its most distinguishing feature is its unique foliage. Submerged leaves are small, narrow, and grow in opposite pairs (decussate) with a sharp point, giving the plant a distinctive, almost 'spiky' or 'thorny' texture. It grows in a compact, bushy habit, creating dense cushions or a plush, shag-rug-like carpet when trimmed regularly.

While often used as a dense foreground carpet, Short's Hedgehyssop is highly versatile and can also be used as a bushy midground 'hedge'. Furthermore, this tissue culture exhibits epiphytic qualities and can be tied to hardscape like driftwood or rocks, eventually attaching itself like a moss or ivy, which makes it an excellent choice for 'aquatic bonsai' designs.

Care & Aquascaping:

• Difficulty: Easy to Moderate (Easier with CO₂ injection). While generally robust, stable water parameters and good lighting are key to its success.
• Placement: Foreground Carpet, Midground Bush, or as an Epiphyte attached to hardscape.
• Lighting: Medium to High is recommended for dense, compact growth. The higher the light, the shorter and denser the plant will grow, promoting a carpet effect.
• CO₂ Supplementation: Highly Beneficial. While the plant can grow without CO₂, supplementation (even with a DIY system) will significantly increase its growth rate, thickness, and overall health. It is not very effective at utilizing bicarbonate for carbon, making CO₂ injection a strong preference for high-quality growth.
• Substrate: It is not overly picky, but a nutrient-rich substrate (like aquasoil) and/or root tabs are highly recommended when planting in the substrate, as it benefits from root feeding.
• Water Conditions: Highly adaptable, but prefers soft and slightly acidic to neutral water (pH 6.0−7.5). It is suitable for a wide temperature range, including cold-water tanks (down to 55°F / 13°C) that may contain native fish or goldfish.
• Propagation: Stem Cuttings. Simply trim the dense stems and replant them into the substrate using tweezers to promote new, dense growth.

Quick Facts

• Scientific Name: Gratiola viscidula Pennell
• Primary Common Name: Short's Hedgehyssop
• Other Common Names: Hedge Hyssop, Viscid Hedgehyssop, Sticky Hedgehyssop
• Origin: North America (Southeastern United States)
• Max Height: 1-8 inches (2-20+ cm), highly variable based on trimming and light.
• Growth Rate: Slow (without CO₂); Medium to Fast (with CO₂)
• Lighting: Medium to High
• CO2 Requirement: Medium (Recommended/Beneficial)
• Water Temperature: 55-85°F (13-29°C)
• Temperament: Peaceful Plant
• Aquarium Use: Foreground Carpet, Midground Bush, Epiphyte