Tuberose (Rajanigandha, Nishigandha) is a popular tropical, highly fragrant, ornamental flower originated in Mexico. The Aztecs grew this plant 600 years ago, but it became popular worldwide in the 16th century. People extract the aromatic oil from its sweet-scented, white, star-shaped blooms arranged on the 12 to 18 inches (30.5 – 46 cm) long spikes.
There are two varieties of Tuberose. Single type (single-row perianth) is an excellent choice for making garland or extraction of essential oil. Double type (two or more rows of perianth) can be a part of bouquet or garden display. Plant this fantastic flower in your garden and enjoy the seductive fragrance of its open blossoms.
|Agave amica (Polianthes tuberosa)|
Single, semi-double, double, and variegated flower
|It starts blooming in July, but the peak period of flourishing is a period from August to September|
|Tuberose thrives best in full sun and can’t bloom correctly in shadow. Provide at least 6 to 8 hours of sunlight daily for it|
|The temperatures from 70 to 75 F (21 – 24 C) are ideal for getting a healthy and vigorous plant|
|Provide fertile, friable, moist, and well-drained soil for your plant, and it will grow healthy and vigorous|
The soil pH
|6.5 to 7.5|
It is highly frost-intolerant plant
|Alocasia, agapanthus, coleus, ferns, canna, colocasia, and caladium|
|Approximately 1 to 1.5 inches (2.5 – 3.8 cm) of water per week will be enough for your Tuberose|
|Apply slow-release, granular fertilizer every three to six weeks from the beginning to the end of the growing season|
The Most Popular Varieties of Tuberose
There are four primary varieties of Tuberoses characterized by the different number of rows of petals. Let’s see.
The fragrant blooms of these plants are pure white. They contain one row of segments with five petals and a high percentage of seeds. The most popular single varieties include:
- Arka Nirantara
- Pune Single
- Calcutta Single
- Kalyani Single
- Hyderabad Single
- Kahikuchi Single
- Single Mexican
- Phule Rajani
- Rajat Rekha
Their white blooms consisting of two to three rows of segments with 10 to 12 petals are arranged on straight stems.
The lightly scented blooms of these plants are white or tinged with pinkish-red. They have more than three rows of segments with 18 to 25 petals. The most popular double varieties include:
- Pearl for Double
- Hyderabad Double
- Culcutta Double
- Kalyani Double
- Swarna Rekha
These streaked leaf-forms have unique stripes and include two artificially produced varieties:
- Rajat Rekha – It is a gamma-ray mutant made by bulbs of flowers exposed to radiation. They have silvery-white stripes along the margins of the foliage.
- Swarna Rekha – It is a gamma-ray double-flowered mutant, with golden-yellow stripes along the margins of leaves.
How to Plant Tuberose
Choose a spot with hot afternoon sun for your flower. Place 4 inches (10 cm) thick layer of compost to encourage good drainage and add necessary nutrients to the soil.
Tuberose has a 5 to 6 months long growing season before start blooming. Therefore, you should start the bulbs indoors if you live in a region with shorter seasons. Begin two months before the last frost.
If you want to plant these flower outdoors, do it in spring when the danger of frost passes and the temperatures during the night are not lower than 60 F (15.5 C).
You can choose to propagate your Tuberose by seeds, bulbs, bulb-segments, or bulblets.
Propagation by bulbs
That is the most common way of propagating Tuberose. The process is quite simple. Purchase individual tuberose bulbs 0.6 inches (1.50 cm) large in diameter, and plant them in your garden.
You should start with planting from March to May, depending on the region you live in, but you can also plant your flower between July and August as well.
The first thing you should do is to grab a garden shovel and dig a 6 to 8 inches (15 – 20 cm) deep hole. Fill half of the hole with the loose, amended soil and place a clump in it. Take care to face buds upward.
Water the ground well and cover bulbs with the 2 inches (5 cm) thick layer of soil. Expect first flowers appearing in late summer or early fall, approximately 90 to 120 days after planting.
Propagation by bulb segments
Since propagation by mature bulbs can be quite expensive, you can use this method. Simply divide 0.8 inches (2 cm) large bulbs into two to three vertical sections.
Take care that each part contains a part of the basal plate with a bud. After treating segments with copper fungicide, you should place them in a rooting medium vertically with a bud facing upward.
It is a hard way to propagate your Tuberose. Sow seeds in January, and you can expect that 70 to 80% of them germinate at some point.
How to Grow and Care Tuberose
The best way is to plant bulbs approximately 8 x 8 inches (20 x 20 cm) or 8 x 12 inches (20 x 30.5 cm) apart. That way, you will provide excellent airflow for your Tuberose.
Your plant will thrive if you prepare fertile, moist, and well-drained ground for it. The best choice is light, friable, loamy, or sandy loam soil with enough nutrients for healthy and vigorous growth. It is also important to check for pH, which should be in a range of 6.5 to 7.5.
Tuberose thrives best in full sun, but airflow and drainage should be excellent as well. Protect your plant from strong winds to get abundant blooming.
Avoid planting this flower in shadow, because you will get tall plants without its desirable, lovely flowers. Therefore, you should provide at least six to eight hours of sunlight a day.
During winter, your plant will need about 16 hours of proper artificial lighting as the equivalent of sunlight. Only that way your Tuberose will flourish.
Tuberose requires subtropical and tropical temperatures. Those from 70 to 75 F (21 – 24 C) are ideal for getting a healthy and vigorous plant.
Take care to provide warm and humid conditions, and protect your flower from the temperatures below 60 F (15.5 C) to avoid any frost damage.
The temperatures above 105 F (40.5 C) will negatively affect the quality of the flowers and spike length.
Water your plant when the top 0.5 to 1 inch (1.2 – 2.5 cm) of the soil surface is dry, and let the excess moisture drains. Use a watering garden can and do it generously, at least once a week throughout the growing season. In general, 1 to 1.5 inches (2.5 – 3.8 cm) of water per week will be enough.
However, take care to keep the plant safe from overwatering, and prevent consequential root rot. Reduce watering gradually when the temperatures fall, and the foliage becomes yellow in autumn.
Since this flower is a heavy feeder, you should apply fertilizer at the beginning of the growing season. The best option is the slow-release, granular ones. Feed the plant every three to six weeks until the growing season ends.
The goal is to encourage blooming, which means that you need to add necessary phosphorus to the ground. At the same time, try to avoid an excessive amount of nitrogen, which encourages the growth of too lush leaves.
Even though Tuberoses requires full sun to blossom abundantly, they can’t stand growing in the dry and cracked ground. Therefore, keep the soil moist by adding a 3 inches (7.6 cm) thick layer of mulch. It will also prevent the growth of weeds.
How to Harvest Tuberose
In India, gardeners grow tuberoses for their flower spikes for commercial purposes. There are two types of harvesting. The first way is collecting flowers as they open day by day.
The second way implies cutting the spikes directly from the plants’ base when one to two pairs of blooms open on the particular spike.
The process is not complicated and begins when Tuberose starts flowering about 80 to 100 days after planting. It is necessary to clip spikes with a sharp gardening knife early in the morning.
The crucial thing is leaving 1.5 to 2.5 inches (3.8 – 6 cm) of a basal part of the scape, to allow the undisturbed growth of bulbs.
Storage the Bulbs
Start with harvesting tuberose bulbs when flowers wilt and the plant stop growing. Approximately 40 to 50 days after blooming, the bulbs will mature. Stop watering your plant, and let the soil becomes dry.
Cut leaves at the ground level and dig out the bulbs. Shake off remained earth adhering on them. Separate bulblets by hand, and prepare them for storing and using at the following season.
The recommended way is to separate bulbs into two groups based on their size:
- Mature – Bigger than 0.6 inches (1.5 cm) in diameter
- Immature – Smaller than 0.6 inches (1.5 cm) in diameter
Place bulbs on a shelf or hang them on the wall to dry or cure. Rotate them regularly to prevent any possible fungal infection and rotting. Some gardeners treat bulbs with 0.2% Bavistin to avoid rotting.
Keep your bulbs at least a month at the temperatures of 65 F (18 C) or six weeks at 85 F (29.5 C) to stimulate their yield.
If you keep your bulbs longer at 85 F (29.5 C), you will improve flower spike yield. On the other hand, their quality will become worse, and the number of produced bulbs will decrease.
Pests and Diseases
Sometimes you may see clusters of these tiny bugs feeding on the foliage and flower buds of your Tuberose. Spray your plant with an appropriate insecticide to get rid of these creatures.
If your plant suffers from this fungal disease, you will see mycelial masses on the surface of the foliage near the ground level.
When the rotting starts, you will see light-green spots extending the whole leaves. The infected leaves will fall from the plant, which will become weak and unable to produce blooms.
In this case, dry rotting of the flowering buds is followed by brown necrotic discoloration of stems. The only thing you can do is to destroy affected plants.
Red spider mites
These creatures appear on the undersides of the foliage when the weather is hot and dry. They suck sap leaves and cause the occurrence of yellow stripes on them. Consequently, the foliage becomes distorted and yellow. Use a soap spray to get rid of these pests.
They feed on flower buds and young foliage, causing the occurrence of damaged flowers and leaves. The problem worsens during the rainy season when your plant may wither.
These needle-thin bugs attack all parts of the plant and suck their juices. You will see discolored flecking on the surface of the foliage. Spread aluminum foil between plants and keep insects away.
Sclerotinia (white mold)
Fungi make a spider web on the growing medium and may climb onto your plant. Once appeared, they will kill your Tuberose. Avoid overcrowding while planting. That way, you will reduce humidity and increase airflow.
These pests lay eggs on growing spikes. Developed larvae feed on buds and blooms, and damage flowers eventually. Try to collect affected flowers to reduce the damage and spray the plant with neem oil.
These worms cause the occurrence of galls (swellings) on roots. The result is a wilted plant. The only you can do is to avoid planting Tuberose into the infested ground.
They feed on plant leaves, make large holes on them, and leave a slime trail everywhere. Handpicking at night and using beer or cornmeal traps are standard methods to get rid of these creatures.
You can also prevent slugs to come close to your Tuberose by placing coffee grounds or diatomaceous earth around stems.
They make burrows in the field and consequently damage planted Tuberose. Use poison bait to kill these menaces effectively.