North America Native Plant

Large Knotgrass

Botanical name: Paspalum paucispicatum

USDA symbol: PAPA13

Life cycle: perennial

Habit: grass

Native status: Native to Puerto Rico  

Large Knotgrass: A Rare Native Grass from Puerto Rico If you’re a native plant enthusiast with a particular interest in grasses, you might have stumbled across the name large knotgrass (Paspalum paucispicatum). This perennial grass species holds the distinction of being native to Puerto Rico, but don’t expect to find ...

Large Knotgrass: A Rare Native Grass from Puerto Rico

If you’re a native plant enthusiast with a particular interest in grasses, you might have stumbled across the name large knotgrass (Paspalum paucispicatum). This perennial grass species holds the distinction of being native to Puerto Rico, but don’t expect to find it at your local nursery anytime soon – this is one of those botanical gems that remains largely under the radar.

What is Large Knotgrass?

Large knotgrass is a perennial grass belonging to the Poaceae family, which includes all true grasses. As its botanical name Paspalum paucispicatum suggests, it’s part of the Paspalum genus, a group known for producing various native and naturalized grasses throughout the Americas. However, this particular species appears to be quite specialized in its distribution.

Where Does It Grow?

This grass species is endemic to Puerto Rico, meaning it’s found nowhere else in the world naturally. Its entire known distribution is limited to this Caribbean island, making it a true regional specialty.

The Challenge for Gardeners

Here’s where things get tricky for anyone interested in growing large knotgrass. This species appears to be poorly documented in horticultural literature, which typically indicates one of two things: it’s either extremely rare in the wild, or it simply hasn’t caught the attention of gardeners and researchers yet.

The lack of available information about its growing requirements, appearance, and garden performance means that even the most dedicated native plant gardener would face significant challenges in cultivating this species. We don’t have reliable information about:

  • Preferred soil conditions
  • Water requirements
  • Sun or shade preferences
  • Mature size and appearance
  • Propagation methods
  • Hardiness zones

A Word of Caution

Given the limited distribution and lack of horticultural information, large knotgrass may very well be a rare species that requires conservation attention. If you’re in Puerto Rico and happen to encounter this grass in the wild, it’s best to observe and appreciate it without disturbing it. Collecting seeds or plants from wild populations of potentially rare species is not recommended without proper permits and expertise.

Alternatives for Native Grass Enthusiasts

If you’re interested in native grasses for your landscape, consider looking into better-documented Paspalum species that are appropriate for your region. Many areas have native Paspalum grasses that are more readily available and have known cultivation requirements. Your local native plant society or extension office can guide you toward suitable alternatives that will give you that authentic native grass experience without the uncertainty.

The Bottom Line

While large knotgrass represents an interesting piece of Puerto Rico’s native flora, it’s not a practical choice for most gardeners due to lack of availability and growing information. Sometimes the most responsible thing we can do as gardeners is to admire rare plants from afar while choosing well-documented native alternatives for our landscapes. If you’re specifically interested in Puerto Rican native plants, focus on species that have established cultivation guidelines and ethical sources – your garden and the local ecosystem will thank you for it.

Large Knotgrass

Classification

Group

Monocot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Liliopsida - Monocotyledons

Subclass

Commelinidae

Order

Cyperales

Family

Poaceae Barnhart - Grass family

Genus

Paspalum L. - crowngrass

Species

Paspalum paucispicatum Vasey - large knotgrass

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA