We are well into 2021 and approaching the end of a cool winter in the greater Baltimore/DC area. With just over a week until spring officially begins, excitement is high for warm air and bright landscapes! The question that we hear from all directions is "When is the grass going to start growing?"
One indicator that the grass is going to start to grow is the familiar, bright yellow shrubs that thrive on a wide range of landscapes - Forsythia!
As soon as the Forsythia begin to bloom with the onset of Spring, you can be sure the grass will start coming out of dormancy soon. Forsythia are deciduous shrubs, shedding their leaves during the winter, and blooming a vibrant yellow flower each Spring. They begin to blossom when their surrounding soil is warmed enough by rising temperatures. Similarly, grass will start growing when soil temperatures are 55 degrees or higher for at least five consecutive days. That means nighttime low temps need to be 55 degrees or higher for five days. Since both depend on warmed soil, you can be sure that bright yellow blossoms will be followed very shortly by bright green blades of grass.
This may be considered folklore by some in the landscaping world, but it holds true time and time again. The forsythia bloom is more tied to air temperature than grass is. Hence, their bloom occurring before grass growth. The air that brings life to forsythia is followed by heated soil and growing grass. Soils in warmer spots, such as long asphalt driveways and south-facing slopes, will be the first areas where grass starts to grow. Overall though, late March through early April is usually the time when the first flush of green grass occurs.
We are approaching the height of turning temperatures, as night temperatures in the 50s are soon to come. However, we have not yet arrived at the stage of grass growth. Currently, the grass is still dormant, since common cool season grasses remain dormant while temperatures are at 40 degrees or below. With night temperatures still dropping to 40 degrees or below in the foreseen future, we are not at forsythia bloom/grass growing quite yet.
But if you have Forsythia plants on your landscape, enjoy those beautiful yellow flowers in the coming weeks! If not, watch for consistent 55 degree or higher temperatures as spring sets in and brings a blanket of bright green back to your property.
Other indicators that the grass is ready to grow include tulips and daffodils. If you see these flowers in bloom, the grass is very close behind!
And last, but definitely not least: Washington D.C.'s beloved Cherry Blossom Festival happens annually from late March to early April. Each year this is another reminder that the grass is ready to grow! This year's peak Cherry Blossom bloom is predicted to take place April 3-5.