Overgrown Ornamental Grasses: How to Keep Them Tidy
Overgrown ornamental grasses can look messy, become unhealthy, or crowd out other plants. There are things you can do to tidy them up and keep them, as well as their neighbors, looking happy and healthy. Join gardening expert Melissa Strauss to find out how.
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Ornamental grasses add texture, movement, and often, year-round interest to the garden. This makes them a versatile and low-maintenance addition to landscapes. They require little care, and most are adaptable to different soil conditions.
With their graceful arching blades, feathery plumes, and varied colors, these plants look beautiful in naturalistic plantings. Many varieties are heat- and drought-tolerant, thriving in sunny spaces. In late summer and fall, their seed heads offer visual interest and serve as a habitat for birds. When left standing in winter, these grasses offer structure and movement in the bare or snowy garden. Their versatility and enduring attractiveness make them highly desirable.
Even though they are typically easy to care for, ornamental grasses can become crowded and overgrown. When this happens, there are several negatives that can occur in tandem. You may encounter center die-out, reduced vigor, and floppy or splitting plants.
Some more aggressive varieties of ornamental grass can be aggressive, sending out runners. They can spread into unwanted places and crowd out nearby plants. Here are some solutions for keeping your overgrown ornamental grasses neat and tidy.
Divide and Replant
As grasses age, they often become crowded or die out in the center. This is especially true of clumping varieties. For most overgrown ornamental grasses, the best solution is to divide them and replant. This task is essential for rejuvenating your plants and maintaining the overall health of the garden. It’s also integral to maintaining their appearance.
One of the best benefits of dividing your plants is that you end up with more plants. You can spread these around different areas of the garden. If you have more than you need, it’s always nice to share with other gardeners. Everyone loves a free plant!
In general, most grasses benefit from division every three to five years. Some more vigorous types may need dividing every other year. This encourages fresh, full, lush new growth. It’s also a good way to get rid of those center portions that may be dying back.
The ideal time to divide your overgrown ornamental grasses is in the spring or fall. In spring, wait until the first new blades begin to grow. This lets you know that they are no longer dormant. In the fall, simply waiting until the weather begins to cool is appropriate.
Cut back the foliage to about six inches, and dig up the entire clump. Use a sharp knife or other garden tool to split the roots into sections. Each section should have both healthy roots and shoots.
Replant your divisions immediately to reduce stress and re-establish those roots. Space them out to allow for future growth, and then water them well. Keep the soil moist, but not soggy, for a few weeks until they’re established. Then, treat them as you ordinarily would.
Cut Them Back Hard
If it’s not a division year, you can do other things to tidy up your overgrown ornamental grasses. Cutting them back hard is an important step in maintaining their appearance and encouraging healthy growth. If you skip this step, you may end up with messy, brown overgrowth that hinders fresh foliage.
The ideal time to hard prune your grasses is in late winter or early spring. Many are attractive when the foliage dries, so they add texture to the garden in winter.
Some gardeners prefer to cut their grasses back in the fall for appearance reasons. However, for the health of the plant, late winter to early spring is the best time, just before new growth appears.
Depending on the type, you can use electric hedge trimmers or shears for this process. Cut them down to between four and eight inches. For taller varieties, you can make this easier by tying the tops together with twine. This will save you a lot of clean-up work.
Cutting back your overgrown ornamental grasses will reinvigorate them. It makes space for new growth to pop up and decreases the risk of disease. As with most plants, pruning encourages vigorous new growth.
Selectively Thin
Another option to tidy up those overgrown ornamental grasses is to thin the plants selectively. If you’re not ready to divide, and there are simply too many in one area, this is a great option.
Sometimes I plant things too close together, and I end up with overly crowded, mature plants. Perhaps you wanted a certain look early on, and planted more than the space could accommodate. That is understandable, but now you may simply have an overcrowded garden that looks messy and unkempt.
If this is the case, the best thing to do is to thin out your plants, giving them all room to breathe and spread out. You don’t have to toss the ones that you removed. It’s easy to replant them elsewhere. Ornamental grasses are adaptable and resilient.
The best time to thin your plants is before the new growth emerges in the spring. However, if you’re not concerned about re-planting the ones that you remove, any time is fine. You may find that transplants have difficulty establishing themselves in the heat of summer.
Another thinning method involves simply trimming up your plants to improve airflow and remove dead foliage. Identify areas that need cleaning up and snip off the unwanted foliage as close to the ground as possible.
This is a great way to improve airflow and prevent fungal diseases. It also makes the garden look neat and tidy, which is what we are hoping for!
Replace When Necessary
The simple truth is that plants don’t live forever. Some may live for a hundred years or more, but this is not the case for ornamental grasses. Some, like fescue and Japanese blood grass, live for only three to five years. Others, like little bluestem or fountain grass, may stick around for up to a decade.
There are long-lived grasses, such as muhly, switchgrass, and reed grass, which can live for 20 years or more. It truly depends on the care. You can be diligent about dividing them and keeping them healthy. If you do, even the shorter-lived types will last much longer.
Ultimately, all grasses will reach an end, and the time will come when there is little to do that will resuscitate them. You may find at some point that your ornamental grasses are simply too overgrown and unruly. They may become ragged and sparse in areas, and just not look tidy anymore.
If you assess your situation and find that this is true, there are two choices. You can remove them and use the space in some alternate way, or you can replace them with new plants. However, with proper care and keeping, you can avoid this for a long time. It just takes a bit of time and effort.
