Can River Buttercup and Slender Hairgrass Grow Together?

River Buttercup and Slender Hairgrass share a workable water window around 20 to 28 °C, pH 6 to 7.5, and 2 to 12 dGH.

Both plants are comfortable in freshwater, so salinity is not a meaningful obstacle.

Both prefer moderate flow, so circulation can be planned as one steady pattern.

Their light and CO2 needs are close enough for one routine: River Buttercup does best with high light and recommended added CO2, while Slender Hairgrass does best with moderate light and recommended added CO2.

Both plants naturally lean toward the foreground, carpeting, and midground, which is why spacing, pruning, and final mature size matter more than they do in a more staggered planting mix.

River Buttercup reaches about 15 cm tall by 20 cm wide, while Slender Hairgrass reaches about 15 cm tall by 10 cm wide. Use those mature sizes for the layout, not the small nursery portions you bring home.

Shade is not the main concern here, which makes the layout easier to keep balanced over time.

River Buttercup is typically rooted in substrate with nutrient-rich substrate preferred and feeds mainly as a mixed feeder. Slender Hairgrass is typically rooted in substrate with nutrient-rich substrate preferred and feeds mainly as a root feeder. That difference can make the pairing easier to arrange than two plants fighting for the exact same root or attachment zone.

Mature size is not the main thing working against this pairing, so normal maintenance is usually enough to keep the scape readable.

Both plants have moderate growth, moderate maintenance, and intermediate difficulty. That makes the maintenance rhythm predictable: watch for crowding, remove old leaves, and avoid letting one clump shade the other for weeks at a time.

The main watch-out is that both plants tend to work in the foreground, carpeting, and midground, so spacing matters more than usual.

The strongest reasons to try the mix are that they share a workable temperature window around 20 to 28 °C; and that their flow preferences sit close enough to tune one layout around both plants.

Use this pairing when you want two plants that can share one routine without forcing a compromise at every step. It is strongest in tanks where mature spacing is planned before the plants fill in.

The simple success test is whether both plants still look healthy after the faster grower has been trimmed several times. If one keeps declining after routine care, the layout is probably asking too much of it.