How to Grow and Care for Grand Duke Jasmine Plant

The Grand Duke Jasmine, known botanically as Jasminum sambac ‘Grand Duke of Tuscany’, is a prized plant among garden enthusiasts. Its appeal lies in the unique, fully double flowers that resemble small, white camellias or roses. These blossoms are celebrated for their potent, sweet fragrance, which can perfume an entire room. This plant also holds cultural significance, as its dried flowers are a traditional component used to flavor jasmine tea. The combination of its exquisite form and memorable scent makes it a sought-after variety.

Grand Duke Jasmine Care Essentials

Providing the right amount of light is a primary consideration. It performs best with at least four to six hours of bright, indirect sunlight daily. Direct morning sun is beneficial, but it should be protected from intense afternoon sun, which can scorch its leaves. When grown indoors, placing it near a sunny window is ideal to encourage vigorous growth and flowering.

Proper watering is fundamental to the health of this jasmine. The goal is to maintain consistently moist soil without it becoming waterlogged, as this can lead to root rot. A practical approach is to water when the top inch of soil feels dry. During the active growing season in summer, it will require more frequent watering, which should be reduced during the dormant winter months.

The right soil composition provides necessary support and nutrients. A well-draining, rich, organic potting mix is recommended to ensure that excess water can escape. This jasmine variety prefers a slightly acidic soil pH. Using a quality potting mix, perhaps amended with peat moss or coconut coir, creates an ideal foundation for a healthy root system.

The Grand Duke Jasmine flourishes in warm and humid conditions. It is well-suited for areas with high humidity but may require assistance in drier indoor environments. To increase ambient moisture, you can place the container on a pebble tray filled with water, ensuring the pot sits on the pebbles and not in the water. Using a room humidifier nearby is another effective method.

Flowering and Fertilizing

Consistent and appropriate fertilization is a driver of abundant flowering, as the plant is a heavy feeder. A lack of nutrients can result in a failure to bloom. To specifically promote blooms, a fertilizer high in phosphorus is beneficial. Look for a product’s N-P-K ratio where the middle number (P for phosphorus) is higher, such as in a 10-30-10 formula.

Fertilize every two to four weeks during the spring and summer when the plant is actively growing. As autumn approaches and growth slows, reduce the frequency of fertilization. Stop feeding entirely during the winter months to allow the plant a period of rest.

This jasmine variety blooms in flushes throughout the warm months. Once a flower has faded, deadheading is beneficial. Snipping off old blooms encourages the plant to redirect its energy into producing new branches and flower buds, leading to a more continuous display.

Pruning for Health and Shape

The primary reasons for pruning are to maintain a compact, bushy shape, improve air circulation, and remove any dead or damaged stems. Because this variety has a slower, more upright growth habit, seasonal pruning helps encourage branching. This in turn leads to more flowers.

It is best to prune after a major flush of flowering has finished to ensure you are not cutting off stems that are developing new flower buds. Pruning in late spring or mid-summer is recommended to shape the plant and spur new growth for subsequent blooms.

When pruning, use clean, sharp shears or scissors to make precise cuts. Locate a spot just above a leaf node—the point on a stem where leaves emerge—and make your cut there. This technique stimulates the plant to send out new shoots from that node, resulting in a fuller, more robust plant structure.

Solving Common Problems

Pests such as spider mites, mealybugs, and aphids can affect the plant. These can be managed with treatments like neem oil or a gentle insecticidal soap. Regularly inspecting the leaves, especially the undersides, can help you catch and address any infestations early.

Yellowing leaves or a lack of flowers are common frustrations that often point back to two fundamental needs: light and nutrition. Yellowing can also be caused by improper watering; overwatering may cause limp leaves, while underwatering makes them crispy. If your jasmine is not blooming or its leaves are yellow, assess if it is receiving adequate light and fertilizer before adjusting your care routine.