Spike plants, often varieties of Cordyline australis or Dracaena indivisa, are popular for their upright, sword-like foliage, adding vertical interest to outdoor spaces. Their architectural form makes them excellent focal points or “thriller” plants in mixed arrangements and garden beds.
Outdoor Planting and Placement
Most spike plant varieties thrive in full sun to partial shade; however, colorful or variegated leaves may retain their vibrant hues better in light shade, which can prevent scorching. Green-leaved varieties generally tolerate more direct sunlight. When preparing the planting site, whether for containers or in-ground, ensure the soil offers excellent drainage.
Spike plants prefer deep, fertile soil rich in organic matter. For in-ground planting, amending heavy clay soils with compost, sand, or peat can improve drainage, while sandy soils benefit from added organic material to help retain moisture. If planting in containers, always select pots with drainage holes to prevent waterlogging. When transplanting, dig a hole at least two to three times wider and twice as deep as the plant’s root ball, backfilling carefully and watering thoroughly to settle the soil.
Spike Plant Outdoor Care
Consistent watering is essential, especially for newly established spike plants. While drought-tolerant once mature, young plants require regular moisture to develop a strong root system. The soil should be kept moist but never soggy, as excessive wetness can lead to root rot. Water when the top 2-3 inches of soil feel dry to the touch.
Fertilization supports robust growth, though spike plants are not heavy feeders. Applying a slow-release granular fertilizer in spring, or a balanced liquid fertilizer at half-strength during the growing season, can provide necessary nutrients. Discontinue fertilization after early fall to allow the plant to prepare for cooler temperatures. Regular removal of any dead or yellowing lower leaves helps maintain the plant’s tidy appearance and overall health.
Common Challenges and Solutions
Yellowing leaves can indicate various issues. Overwatering or underwatering are common culprits, as both can stress the plant and lead to discoloration. Yellowing can also be a sign of nutrient deficiency, too much direct sunlight, or the natural aging process of lower leaves. Ensuring proper watering practices and adequate light exposure often resolves these problems.
Browning leaf tips are a frequent concern, often linked to low humidity, inconsistent watering, or salt buildup from tap water. Using filtered water or allowing tap water to sit overnight before use can help mitigate issues caused by fluoride or other minerals. Pest infestations, such as spider mites or mealybugs, can also lead to leaf discoloration and a weakened plant. Prompt identification and treatment with horticultural oils or insecticidal soaps are effective solutions.
Winterizing Outdoor Spike Plants
Protecting spike plants is often necessary in cold winter regions, as many varieties are not fully cold-hardy. Cordyline australis can typically survive outdoor winters in USDA Zones 8-11, tolerating temperatures down to about -5°C (23°F), but may experience foliage damage. In these zones, mounding a 6-8 inch layer of organic mulch, such as shredded bark or straw, around the base of in-ground plants helps protect the roots.
For those in colder climates (USDA Zones 3-7), or for Dracaena indivisa which is less cold-tolerant, containerized plants should be moved indoors before the first frost. An ideal indoor location for overwintering is a bright, cool room with temperatures around 10-15°C (50-59°F). During this period, reduce watering significantly, providing just enough to prevent the soil from drying out completely, as the plant’s growth slows.