Tuberose: Tender Bulb
Planting in the Garden:
- Plant bulbs outside after all danger of frost has passed and daytime temperatures remain above 70 degrees.
- Select a sunny site or container with good drainage protected from wind.
- Prepare the bed by turning the soil under to a depth of 8 inches. Level with a rake to remove clumps of grass and stones.
- Most plants respond well to soils amended with organic matter. Compost is a wonderful form of organic matter with a good balance of nutrients and an ideal pH level, it can be added to your planting area at any time. If compost is not available, top dress the soil after planting with 1-2 inches of organic mulch, which will begin to breakdown into compost. After the growing season, a soil test will indicate what soil amendments are needed for the following season.
- Dig a hole for each bulb large enough to amply accommodate the bulb, plant 3 inches deep and 6 inches apart with the pointy side up.
- Firm gently and water.
How to Grow
- Keep weeds under control during the growing season. Weeds compete with plants for water, space and nutrients, so control them by either cultivating often or use a mulch to prevent their germination.
- Mulches also help retain soil moisture and maintain even soil temperatures. For annuals an organic mulch of shredded leaves lends a natural look to the bed and will improve the soil as it breaks down in time. Always keep mulches off a plant’s stems to prevent possible rot.
- Keep plants well-watered during the growing season, especially during dry spells. Plants need about 1 inch of rain per week during the growing season. Use a rain gauge to check to see if you need to add water. It's best to water with a drip or trickle system that delivers water at low pressure at the soil level. If you water with overhead sprinklers, water early in the day so the foliage has time to dry off before evening, to minimize disease problems. Keep the soil moist but not saturated.
- After new growth appears, a light fertilizer may be applied. Keep granular fertilizers away from the plant crown and foliage to avoid burn injury. Use low rates of a slow release fertilizer as higher rates may encourage root rots.
- Monitor for pests and diseases. Check with your local Cooperative Extension Service for pest controls recommended for your area.
- Tuberoses are hardy in zones 7 or 8-10, but need to be dug up and stored over the winter in cooler zones. In the fall before frost or when the foliage begins to die back, dig up the bulbs with the soil and tops clinging to them. Cut the foliage to about 2-3 inches from the bulb and allow to dry in a warm location with good air circulation for 4-7 days. Store bulbs at about 50-60 degrees F. Plant again in spring.
- Flowers are exceptionally fragrant and good for cutting. Cut when there are 2-4 open blooms per spike.
- May also be grown as a house plant.
Common Disease Problems
Alternaria Leaf Spot: Small, round reddish brown spots with white to grey centers form on the upper surface of the leaves and along the midrib. The lesions may encircle the stems and cause wilt. This disease is worse in warm, wet or very humid weather. Burpee Recommends: Avoid getting water on the foliage. Remove infected plant parts and do not work around wet plants. Provide plenty of air circulation. Contact your Cooperative Extension Service for fungicide recommendations.
Bacterial Leaf Spot: First signs are small translucent spots with a broad yellowish edge that slowly enlarge and become angular or irregularly circular with a reddish center. It thrives in cooler temperatures. The disease may also affect and disfigure flower heads. Burpee Recommends: Remove infected plants. Rotate crops with plants in a different family. Avoid overhead watering. Do not work around plants when they are wet.
Botrytis: This fungus causes a grey mold on flowers, leaves, stems and buds. It thrives in cool wet weather conditions. Burpee Recommends: Remove affected plant parts, avoid watering at night and getting water on the plant when watering. Make sure plants have good air circulation. Contact your Cooperative Extension Service for fungicide recommendations.
Root Knot Nematodes: Microscopic worm-like pests that cause swellings (galls) to form on roots. Plants may wilt or appear stunted. This is a serious problem in many Southern states. Burpee Recommends: Do not plant into infested soil. Try planting ‘Nema-Gone’ marigolds around your plants.
Sclerotinia: Also called white mold, this fungus looks like a spider web crawling on the surface of the growing medium. It can climb onto plants and kill them in time. Burpee Recommends: Decrease humidity and increase air circulation. Avoid overcrowding plants.
Common Pest and Cultural Problems
Aphids: Greenish, red, black or peach colored sucking insects that can spread disease as they feed on the undersides of leaves. They leave a sticky residue on foliage that attracts ants. Burpee Recommends: Introduce or attract natural predators into your garden such as lady beetles and wasps who feed on aphids. You can also wash them off with a strong spray, or use an insecticidal soap.
Slugs: These pests leave large holes in the foliage or eat leaves entirely. They leave a slime trail, feed at night and are mostly a problem in damp weather. Burpee Recommends: Hand pick, at night if possible. You can try attracting the slugs to traps either using cornmeal or beer. For a beer trap, dig a hole in the ground and place a large cup or bowl into the hole; use something that has steep sides so that the slugs can’t crawl back out when they’re finished. Fill the bowl about ¾ of the way full with beer, and let it sit overnight. In the morning, the bowl should be full of drowned slugs that can be dumped out for the birds to eat. For a cornmeal trap, put a tablespoon or two of cornmeal in a jar and put it on its side near the plants. Slugs are attracted to the scent but they cannot digest it and it will kill them. You can also try placing a barrier around your plants of diatomaceous earth or even coffee grounds. They cannot crawl over these.
Spider Mites: These tiny spider-like pests are about the size of a grain of pepper. They may be red, black, brown or yellow. They suck on the plant juices removing chlorophyll and injecting toxins which cause white dots on the foliage. There is often webbing visible on the plant. They cause the foliage to turn yellow and become dry and stippled. They multiply quickly and thrive in dry conditions. Burpee Recommends: Spider mites may be controlled with a forceful spray every other day. Try hot pepper wax or insecticidal soap. Check with your Cooperative Extension Service for miticide recommendations.
Thrips: Thrips are tiny needle-thin insects that are black or straw colored. They suck the juices of plants and attack flower petals, leaves and stems. The plant will have a stippling, discolored flecking or silvering of the leaf surface. Thrips can spread many diseases from plant to plant. Burpee Recommends: Many thrips may be repelled by sheets of aluminum foil spread between rows of plants. Remove weeds from the bed and remove debris from the bed after frost. Check with your Cooperative Extension Service for pest controls.
Vine Weevil: This insect cuts irregular notches in leaf margins and grubs feed on plant roots, sometimes causing the death of the plant. Adults are approximately 5/16 inch long, dull black with dirty yellow marking on the wing cases. The grubs are c-shaped, 3/8 inches long, with light brown heads. Burpee Recommends: Handpick adults at night, shake the plants over newspaper to dislodge them. Check under pots where they hide during the day. Check with your Cooperative Extension Service for pesticide recommendations.
Can I start my tuberoses inside? Yes, you can plant the bulbs early indoors about eight weeks before the last frost for a head start.
Why didn’t my tuberose bloom? Tuberoses can be slow growing plants and in general take about four months to bloom from starting growth. Other reasons could be not enough sunlight, too much nitrogen or stress. Tuberoses need constant moisture and should not be allowed to dry out.
Do I need to divide my tuberose? Before planting remove offsets and plant them separately. They may take a couple of years to bloom.