Early spring rounds of golf are always exciting after a long winter, but don’t be surprised if the greens look a little strange for a while. Greens that are comprised of bentgrass, Poa annua, or a mix of both grasses, can have a mottled or blotchy appearance coming out of winter – a patchwork quilt with various shades of green, yellow, purple and other colors. It might look like there’s something wrong, but this multicolored appearance is usually just a seasonal symptom of genetic differences among the individual grass plants on the greens.

Why do the greens look like that?

Some bentgrass greens are seeded with a blend of different varieties, which can lead to differences in appearance across the playing surface that are often most noticeable during seasonal shifts as one variety reacts differently than another. Even if the greens were originally seeded with a single variety of bentgrass, minor genetic differences between individual plants will develop and become amplified over time, leading to differences in appearance that are, again, most noticeable during seasonal transitions. Natural segregation of bentgrass does not typically affect putting performance because the growth rates and leaf texture of the varieties are typically very similar, even if the colors look quite different coming out of winter.

Poa annua greens can be great putting surfaces, but they are rarely made up of a single, uniform variety of this highly adaptable grass species. Instead, they consist of many different “biotypes” or “ecotypes” that have evolved over time. These genetically different biotypes may look similar in summer when they are all actively growing, but they can behave very differently coming out of winter. For example, some will start growing quicker than others as temperatures warm in the spring – giving them a greener color than the biotypes that are still recovering from winter. Even if the surface is smooth and healthy, natural diversity among the Poa annua plants can create a mottled appearance.

Many greens are also a mix of creeping bentgrass and Poa annua. In these situations, you will see color variations within each grass species and differences between the two. Poa annua is ready to get up and go as soon as temperatures warm up in the spring, while creeping bentgrass is still in its pajamas for a while. As a result, patches of Poa annua will typically look greener much earlier. Aesthetics aside, the different growth rates of Poa annua and creeping bentgrass in early spring can make it challenging for superintendents to maintain smooth ball roll until temperatures are warm enough for both grasses to be actively growing. If greens contain a high percentage of Poa annua, mowing will typically begin a little earlier to ensure the faster-growing grass doesn’t create an uneven surface alongside the slower-growing bentgrass. Plant growth regulators, fertility management, rolling greens, sand topdressing and other practices can also help minimize the impact of different growth rates early in the season.

A normal part of spring

Differences in plant genetics, species composition and growth rates all contribute to temporary color variation on cool-season greens in late winter and early spring. Playability impacts are typically minimal, and if you’re worried about how the greens look, you can rest assured that this colorful phase is usually short-lived. As temperatures get consistently warmer and growth increases for all types of bentgrass and Poa annua, the greens will regain a more-uniform appearance. If you think that the greens may have been damaged by disease or winter injury, don’t hesitate to reach out to the superintendent for an update – but most likely what you are seeing is just different grasses waking up in their own ways after a long winter sleep.