Aralia cordata

Spikenard thrives in moderate sun exposure but can also grow in lower light conditions, similar to its natural habitat on the forest floor. It requires sunlight for healthy growth, but too much direct exposure can be harmful. The plant generally needs about 3-6 hours of sunlight daily, which is considered partial sun. For locations with full shade, it's important to ensure they receive less than 3 hours of sunlight. Observing how sunlight moves through your garden and choosing locations that offer a balance of light and shade is crucial for the plant's well-being.

Indoor Spikenard plants require adequate lighting to grow optimally, especially when natural sunlight is not sufficient, such as during winter or in less sunny spaces. Artificial lighting, such as LED lights, is a beneficial solution that promotes healthier, faster growth by providing the necessary wavelengths of light. For plants needing full sun, the requirement is 30-50W per square foot, while partial sun plants require 20-30W, and full shade plants need 10-20W. The light source should be placed 12-36 inches above the plant, mimicking natural sunlight, and most plants benefit from 8-12 hours of light per day to thrive indoors.

When Spikenard receives insufficient light, it may exhibit several symptoms, including the growth of smaller leaves compared to previously matured ones, leggy or sparse growth due to longer spaces between leaves or stems, faster leaf drop as a survival response to conserve resources, slowed or halted leaf production, and the appearance of lighter-colored or irregularly patterned new leaves. Insufficient sunlight can also lead to chlorosis, where leaves lose their green color, as well as other conditions like sunscald, leaf curling due to reduced surface area exposure, wilting from loss of turgor pressure, and leaf scorching from excessive sunlight exposure. These symptoms highlight the plant's struggle to adapt to insufficient light conditions.

To help Spikenard adapt to changing light conditions, gradually increase its exposure to sunlight by moving it to sunnier spots each week until it receives 3-6 hours of direct sunlight daily. For indoor plants that are large or not easily movable, consider using artificial light, such as a desk or ceiling lamp for at least 8 hours daily, or invest in professional plant grow lights. Outdoors, it's crucial to avoid sudden changes in light intensity by gradually moving plants to sunnier locations to prevent sunburn. Additionally, minimizing obstructions like pruning trees can help, and for smaller plants, transplanting during the dormant period to a location with ample sunlight and good drainage can be beneficial. Note that parts of the plant affected by prior insufficient sunlight may not recover fully, but new growth will be healthy with improved light exposure.

Spikenard flourishes in temperatures ranging from 41 to 95 °F (5 to 35 °C). It is a plant that has strong cold resistance and does not typically need special frost protection measures during winter. However, during the colder months, maintaining a warmer indoor environment is beneficial for its growth. In regions where the temperature may fall below -30°C, it is crucial to offer protection against the cold by covering the plant with insulating materials like soil or straw. Additionally, watering the plant abundantly before the first freeze in autumn is recommended to keep the soil moist, which helps prevent drought and water scarcity throughout the winter and early spring.

Spikenard shows a remarkable tolerance to cold, thriving best when temperatures are maintained above 5°C. However, during winter, it should be kept from falling below -25°C. Exposure to temperatures below -30°C might not visibly affect the plant during the winter, but it can lead to reduced sprouting or lack thereof during the spring. If such a situation occurs, the recommendation is to remove any parts of the plant that have failed to sprout in the spring, as a solution to encourage healthy new growth.

In the summer, it is crucial to keep Spikenard's surrounding temperature below 35°C to prevent heat stress. Exceeding 38°C may cause the plant's leaves to lighten in color, curl, become prone to sunburn, and in severe cases, the plant can wilt and dry out completely. To mitigate these effects, trim away any sunburned and dried parts of the plant. Moving it to a location that offers shade during the midday and afternoon sun, or utilizing a shade cloth, can protect it. Additionally, watering the plant in the morning and evening helps in keeping the soil moist, further aiding in its recovery and health during hot conditions.