The graceful, flowing leaves and showy plumes of ornamental grasses add a unique texture, movement, and visual interest to gardens. While most varieties are low-maintenance, fertilizing them every once in a while can help them grow lushly and healthily, with bright colors and lots of blooms. But there are so many fertilizers out there, how do you choose the right one? This full guide will tell you which ones are best for ornamental grasses for the best health.
Do Ornamental Grasses Need Fertilizer?
Many popular ornamental grasses like Miscanthus Pennisetum, and Panicum are prized for their cold hardiness striking form, and winter appeal. The grassy fronds provide aesthetic value through fall and winter when most plants are dormant.
Once they are established, ornamental grasses don’t need much care other than being divided every so often and cleaned up in the spring. But do they need fertilizing?.
Generally, fertilizer is not essential for ornamental grasses. Most varieties thrive in low fertility soils and can flop over with excessive feeding. However, applying a small amount of fertilizer can boost grass growth, color, and flowering. If plants show signs of nutrient deficiency, fertilizer is recommended to rejuvenate them.
How Much to Fertilize Ornamental Grasses
When fertilizing ornamental grasses, moderation is key. Too much fertilizer leads to floppy, weak foliage with poor winter hardiness. A good rule of thumb is to apply 1⁄4 cup of granular fertilizer or organic matter per mature plant in early spring as growth resumes. Liquid fertilizers should be diluted to half strength before applying according to package directions.
Slow release fertilizers are ideal to provide a gradual nutrient boost over several months. Natural organic options like compost, manure, and bone meal also work well. Test soil first and only apply what is needed to avoid overfeeding.
Best Fertilizers for Ornamental Grasses
All-Purpose Granular Fertilizer
For balanced nutrition, choose an all-purpose granular fertilizer with equal parts nitrogen, phosphorus, and potassium like 10-10-10 or 12-12-12. Apply at 1⁄2 pound per 1,000 square feet around grasses in early spring. Gently scratch into the soil surface. Avoid overapplying.
Organic Fertilizer
Compost, manure, alfalfa meal, and bone meal are all organic foods that are good for you. In early spring, work 1.25 to 2 inches of compost or 2.25 to 3 pounds of manure into the ground around grass. Organics break down slowly for gradual nutrient release.
Liquid Fertilizer
Liquid fertilizers such as fish emulsion, seaweed extract, and soluble mixes (20-20-20) allow customizable feeding. Apply according to package directions 2-4 times per season after new growth begins. Always water in immediately after applying.
Slow Release Fertilizer
Slow release fertilizers like Osmocote and Scotts Feed Your Lawn provide an extended nutrient release over many months. Apply granular types at half strength in early spring. Avoid overapplying slow release fertilizers.
Natural Fertilizer
Natural fertilizers including wood ash, bone meal, and rock powders deliver gentle nutrition over time. Work 1-2 cups per large grass into soil around roots in early spring. Only apply what is needed based on soil test results.
Fertilizing Ornamental Grasses in Pots
Container grown ornamental grasses require more frequent fertilization than in-ground plantings to maintain health. Apply a balanced liquid fertilizer every 2-3 weeks during the growing season at half strength. You can also topdress containers with worm castings or slow release granules in spring.
When to Fertilize Ornamental Grasses
It’s best to fertilize ornamental grasses in early spring, right before they start to grow new leaves. This makes it easy for plants to get nutrients when they wake up from their winter sleep. Established grasses may only need fertilizing every 2-3 years. Don’t feed plants too late in the fall, when they are getting ready for winter.
Signs Ornamental Grasses Need Fertilizer
- Smaller growth/less abundant flowering than previous years
- Loss of vivid color/faded, yellowing foliage
- Slow growth
- Thinning or dieback
- Stunted, spindly new growth
Tips for Fertilizing Ornamental Grasses
- Always follow package directions carefully to avoid overfeeding
- Water in fertilizers thoroughly after applying
- Limit feeding established grasses to early spring every 2-3 years
- Reduce liquid fertilizer strength to 1/2 concentration
- Test soil first and only apply nutrients that are needed
- Apply lower amounts of fertilizer more frequently versus heavy feeding
While ornamental grasses are adaptable, low maintenance plants, occasional fertilization provides a boost of nutrients to keep them looking their best. Choose an organic, slow release, or balanced liquid fertilizer applied lightly in spring to promote healthy grass growth without excess. With a gentle feeding regime, ornamental grasses will thrive for years of beauty and interest in the garden.
When Should You Fertilize?
Research shows that woody plants actively absorb nutrients from the soil during the growing season and require few nutrients during the dormant winter season (see Figure 1). Therefore, apply fertilizer as soon as the plants begin breaking dormancy in the spring, and avoid fertilizing after the first fall frost, which signals plants to begin resting for the winter.
Which Analysis Is Best?
A soil test, available through your county Extension office, is the best way to determine which fertilizer analysis is best for your soil. As a general rule, most ornamental plants will do better with fertilizer that has a 3-1-2 or 4-1-2 ratio of its main nutrients (nitrogen, phosphorus, and potassium [N-P-K]). A 12-4-8 fertilizer, for instance, is a 3-1-2 ratio, and a 16-4-8 fertilizer is a 4-1-2 ratio. Research shows that phosphorus, the middle number in the analysis, is held be soils and does not leach with rains or irrigation as nitrogen or potassium do; so it is usually needed in lower amounts. On new sites where phosphorus has never been applied, a complete balanced fertilizer such as 8-8-8 or 10-10-10 is sometimes recommended.
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FAQ
What fertilizer do you use for ornamental grasses?
For the best care, fertilize sparely in the spring with a slow-release fertilizer such as 3-1-2 or 4-1-2 ratio.
What is the best food for ornamental grasses?
Multi Purpose 10-10-10 Fertilizer works well. It’s the same process to use Miracle Gro 20-20-20 liquid fertilizer as it is to water, but the fertilizer is mixed in. It should be done 3 or 4 times per year starting in late April and stopping in mid July. Organic fertilizers, like manure, can also be used with good results.
Can you put Miracle Grow on ornamental grass?
A month after planting, give your new ornamental grasses a nutritious meal of Miracle-Gro® Shake ‘n Feed® All Purpose Plant Food to keep them growing strong.
How do you keep ornamental grasses looking good?
You don’t have to water ornamental grass very often because it can handle drought, and most pests don’t like the taste of it. You only have to cut them back occasionally to eliminate the brown grass and keep it from dying. Additionally, you will have to divide it every few years.
What is the best fertilizer for ornamental grasses?
Organic fertilizers are gentle and easy for plant roots to uptake, as well as healthy for the entire garden. If you want to feed ornamental grasses something organic, like compost, leaf mold, mushroom manure, or other organic materials that are easy to break down, You may also choose to use a basic 10-10-10 balanced food.
What is the best fertilizer for fountain grass?
Excess food can also cause an unstable plant with limp blades. In the first year, fountain grass can benefit from some organic fertilizer applied at planting time. Alternatively, the best fertilizer for fountain grass is a time release fertilizer that will last through summer and help the plant build a vigorous root system and initial form.
Does fertilizer help ornamental grass grow?
Still, a little fertilizer can help an ornamental grass flourish, especially if a mature plant is a few years old and the soil lacks fertility. This is common when growing the grasses in containers, since the nutrients present in the original potting mix fade with time.
How do you fertilize ornamental grass?
If you want to fertilize ornamental grass, use a balanced, slow-release fertilizer like Osmocote 14-14-14. You can avoid fertilizers designed to encourage flowering. Ornamental grasses need little fertilizing. Avoid fertilizing in fall, winter, or on hot summer days. Apply fertilizer in spring when new growth appears.
How much fertilizer should I put on ornamental grass?
If your grasses take on a faded color and look less than vigorous, a small amount of fertilizer will perk them up. When fertilizing ornamental grasses, remember that less is more; err on the sparse side when feeding the plants. A general rule of thumb is to apply ¼ cup (59 ml.) per plant in the spring as growth starts back up.
Should ornamental grass be fertilized?
Fertilizing ornamental grasses with the same food you use on the lawn might seem logical, but think about what happens when the lawn gets fertilized. The grass grows very rapidly. If ornamental grasses go on a sudden growth spurt, they tend to flop over, losing their aesthetic value.