Drought Tolerance of Pampas Grass

Characteristics

• Pampas grass is a vigorous plant that grows quickly, developing a large clump of narrow, grasslike leaves that can be 10 feet long. The leaves radiate from the plant's center and arch gracefully, giving the effect of a fountain. In midsummer, pampas grass produces tall, 1-foot-long flowering plumes in white or pale pink that extend above the clump. The feathery plumes stay on the plant well into winter, while the foliage slowly turns golden brown. The plant can be up to 12 feet tall and spread to cover 4 to 6 feet, although several dwarf varieties are also available.

Water

• Pampas grass originated in South America, where it grows as a native plant on mountains or on the banks of rivers and streams. In spite of growing in areas with good moisture, cultivated pampas grass is quite adaptable to dryness once established. It benefits from receiving extra water during dry spells during its first year or two, but once its roots have spread broadly and deeply, pampas grass develops into a tough plant that can withstand extended periods of drought. It's also tolerant of salty air and does well in coastal areas, even in locations where rain is scarce.

Conserving Moisture

• A few strategies can help pampas grass come through long dry spells without any damage or slowing of its growth. The plant prefers a sunny spot, but choosing a location where it receives some light afternoon shade can protect it from drying of the soil caused by intense sun, especially in areas with hot summer afternoons. The plant's abundant foliage helps provide some natural shade and cooling of its roots, but you can increase this and also conserve soil moisture by adding a 2- to 3-inch-thick layer of organic mulch each spring, renewing it during the season as it breaks down.

Drainage

• Pampas grass prefers a well-drained loam that doesn't tend to stay soggy and doesn't tolerate soil that contains abundant clay and holds water for extended periods. You can test your soil's drainage by digging a hole about 1 foot deep and filling it with water. Once the water drains away, re-fill the hole and measure the water's depth, then measure again after 15 minutes, to determine how many inches of water have drained away. This amount multiplied by four is your soil's drainage per hour. A value of less than 1 inch per hour indicates poor drainage. In that case, add sand to your site and re-test its drainage before planting, aiming for a value of about 4 to 6 inches per hour for best results.