I absolutely love pampas grass in my garden — those tall, elegant plumes really make a statement. But I’ve learned that to keep pampas grass looking its best, it needs more than just good soil and sunlight. Proper fertilizing is key to helping it grow strong and beautiful each year. Let me share what I’ve found about when, how, and with what you should feed your pampas grass for the best results.
Hardly any grass is as striking as pampas grass. The large clumps with their tall flower plumes only develop well in a suitable location with good care and sufficient nutrients.
Pampas grass (Cortaderia) is a favorite of many garden enthusiasts. However, its splendor does not come automatically. The ornamental grass only thrives optimally when it has enough nutrients available. In its native South American habitat, the plant’s dead parts decompose in the soil after each growing season, largely providing fertilizer for new growth. In the garden, however, we usually cut back the dry material in early spring. Since the cut plumes decompose slowly and look unsightly if left on sunny beds, they are shredded and put on the compost. Because pampas grass cannot maintain its nutrient cycle naturally in this way, it needs regular fertilization.
I’ve noticed that sometimes it takes a bit of trial and error to figure out the right amount of fertilizer and timing. Each season feels like a new learning experience, but seeing those tall, fluffy plumes grow stronger and healthier makes all the effort totally worth it.
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When Should You Fertilize Pampas Grass?
It is advisable to cut back pampas grass in early spring. By the end of March at the latest, the grass will begin to stir again, showing new green shoots. This is exactly when pampas grass needs nutrients, and the first fertilization of the year should be applied. For plants grown in beds, two more fertilizer applications should follow at two-month intervals. If the soil at the location is very sandy and well-drained, fertilize a total of four times a year at intervals of about six weeks.
Pampas grass grown in pots or containers should be fertilized more frequently because nutrients are washed out of the soil when watering, escaping through drainage holes.
Fertilizing Pampas Grass: The Essentials at a Glance
- Pampas grass needs sufficient nutrients for optimal growth.
- The first fertilization should be in spring, followed by two more applications every two months.
- Pampas grass in pots requires more frequent feeding because nutrients wash out more easily.
- Suitable fertilizers include compost, horn shavings (hornspäne), horn meal, or other organic fertilizers.
- Pay attention to the nitrogen content — it should not be too high.
What Fertilizer Should You Use for Pampas Grass?
Organic fertilizers have proven effective outdoors because they increase the soil’s humus content over time. Compost is an excellent choice. Later in the season, horn shavings or horn meal are recommended. Any other organic fertilizer is also welcome. However, be careful that the fertilizer is not too rich in nitrogen — this can easily happen with compost.
A balanced ratio of the main nutrients nitrogen, phosphorus, and potassium is very important. Too much nitrogen promotes rapid growth but results in relatively soft plant tissue. The plants then have poor structural stability, are less frost-resistant, and do not overwinter as well as they could. Potassium stabilizes cell walls, and phosphorus supports good flower development.
For pampas grass in pots, liquid mineral-based fertilizers with a not-too-high nitrogen content are better, since they do not need to be broken down first by soil microorganisms.
How to Fertilize Pampas Grass?
In beds, compost is generously worked into the soil around the plants in spring. Keep the soil mildly moist in spring, because if there is drought (which can occur even in April or May), soil microorganisms cannot release the nutrients from the compost in a plant-available form.
If no compost is available, you can use commercial compost soil, aged manure, or horn shavings as fertilizer. Horn shavings or horn meal are well suited for the follow-up fertilizations during the year. All of these are worked into the soil around the ornamental grasses.
Liquid fertilizer for pampas grass in pots has the advantage that doses can be controlled with each watering. There are also long-term fertilizers — usually organic-mineral blends — that last an entire season as they dissolve gradually. However, since nutrients are washed out of pots, even long-term fertilizers should be applied three times a year, from March to the end of July.
With the right care and regular fertilizing, pampas grass can thrive and become a stunning focal point in your garden. It’s worth the effort to give it the nutrients it needs, especially after winter. I hope these tips help you enjoy healthy, vibrant pampas grass season after season.
