Overview
Helianthus ×doronicoides Lam. (pro sp.) is a herbaceous perennial flowering plant, which belongs to the family Asteraceae. The plant is a hybrid of Helianthus decapetalus and Helianthus pauciflorus, native to North America.
Common Names
The plant is commonly known as Smooth Oxeye, Thick-leaved Sunflower, and False Sunflower.
Appearance
Helianthus ×doronicoides Lam. (pro sp.) typically grows up to a height of 3 to 6 feet tall and spreads up to 2 to 3 feet wide. The plant has bright yellow flowers, which bloom during the months of August and September. The flowers have a black central disk and are surrounded by yellow petals. The leaves are thick, long, and lance-shaped, with a rough texture, green in color, and slightly hairy.
Uses
Helianthus ×doronicoides Lam. (pro sp.) is commonly used for ornamental purposes in gardens and landscapes. The plant is a popular choice due to its bright yellow flowers, which attract bees, butterflies, and other pollinators. It can also be used as a cut flower. In addition, the plant is used in traditional medicine to treat various ailments, including respiratory infections, fever, and wounds.
Growth Conditions for Helianthus ×doronicoides Lam.
Helianthus ×doronicoides Lam. (pro sp.) is a hardy perennial plant that is native to the United States. This plant is commonly known as the smooth oxeye or Lanceleaf sunflower.
Light Requirements
Since Helianthus ×doronicoides Lam. (pro sp.) is a sunflower, it needs a lot of sunlight (about 6 hours daily) to grow appropriately. It will thrive best in full sunlight as its leaves orient themselves to face the sun.
Temperature Requirements
Helianthus ×doronicoides Lam. (pro sp.) requires temperate weather conditions to grow appropriately. It will grow best in USDA Hardiness Zones 4 to 9. It can withstand cold temperatures of up to -29°C. However, high temperature during the plant's flowering phase could result in low pod and seed sets.
Soil Requirements
Helianthus ×doronicoides Lam. (pro sp.) prefers well-drained soils, including loamy and sandy soils. It is essential to maintain the soil pH between 6.0 and 7.5. The plant can tolerate occasional drought but will do better when water is sufficiently available.
The soils must have some organic matter to ensure continuous growth and healthy plant development. It is also necessary to ensure proper soil drainage as standing water could cause root rot, which would impact negatively on the plant's growth.
Cultivation methods
Helianthus ×doronicoides Lam. is a low-maintenance plant that can be grown in USDA Hardiness Zones 3 to 9. It prefers full sun and well-draining soil. The plant should be planted in a location where it can receive at least six hours of direct sunlight.
The plant can be propagated through division in spring or fall. Propagation through seeds is also an option, and seeds should be sown in the spring. The recommended spacing for Helianthus ×doronicoides is 12-24 inches apart.
Watering needs
Helianthus ×doronicoides requires a moderate amount of water. The soil should be kept evenly moist, but not waterlogged. During the growing season, the plant should be watered every 7-10 days, or more frequently during periods of drought or high temperatures.
Fertilization
Helianthus ×doronicoides does not require heavy fertilization. A light application of a balanced fertilizer (10-10-10) in the spring is sufficient. Over-fertilization can lead to excessive foliage growth and reduced flower production.
Pruning
Helianthus ×doronicoides does not require regular pruning. Deadheading spent flowers can encourage the plant to produce more blooms. In the fall, the plant can be cut back to the ground to promote new growth in the spring. Additionally, the plant may benefit from pinching back the tips of the stems in late spring to promote branching and a bushier form.
Propagation of Helianthus ×doronicoides Lam. (pro sp.)
Helianthus ×doronicoides Lam. (pro sp.) can be propagated through various methods such as:
Seed Propagation
The easiest and most common method for propagating Helianthus ×doronicoides is through seeds. The plant produces seeds after flowering which can be collected and sowed in well-drained soil. Sow the seeds about 10 to 15mm deep and water them regularly. The seeds should germinate in about 14 to 21 days.
Division Method
Helianthus ×doronicoides can also be propagated through division method. It is best to divide the plant in early spring, just as new growth appears. Dig up the plant and divide the roots into smaller sections. Replant the divided sections in well-draining soil, placing them at the same level as the original plant. Water the plant regularly until it establishes roots.
Cuttings
The plant can also be propagated through cuttings. Take 3 to 4-inch cuttings from the plant, remove the lower leaves, and plant them in well-draining soil. Keep the soil moist and warm. In about 8 to 10 weeks, the cuttings should start rooting and growing new leaves.
Regardless of the propagation method, provide the plant with sufficient water and sunlight to ensure healthy growth.
Disease and Pest Management for Helianthus ×doronicoides Lam.
Helianthus ×doronicoides Lam. is a sunflower species that is generally resistant to many pests and diseases if cultivated in the appropriate conditions. However, it can still be attacked by several pests and diseases that may affect its growth, yields, and quality. The following are some common diseases and pests that might affect Helianthus ×doronicoides Lam. and ways to manage them:
Common Diseases
1. Downy Mildew
This disease is caused by the fungus Peronospora spp. and can cause yellowing and wilting of the leaves, stunted growth, and poor yields. It thrives in cool, humid conditions, especially in poorly drained soils. To manage this disease, ensure proper drainage and good air circulation, avoid overhead watering, and apply fungicide sprays when necessary.
2. Sclerotinia Head and Stem Rot
This disease is caused by the soil-borne fungus Sclerotinia sclerotiorum. It can cause wilting, yellowing, and premature death of leaves, as well as rotting of stems and heads. The fungus can survive in the soil for several years, making crop rotation important. To manage this disease, ensure proper soil drainage, good air circulation, and avoid overcrowding the plants. Apply fungicide sprays when necessary.
Common Pests
1. Sunflower Beetle
These beetles feed on the leaves, flowers, and heads of sunflowers, causing extensive damage. The larvae tunnel into the stems, causing wilting and stunted growth. To manage this pest, handpick and destroy the beetles and larvae, and use insecticidal soaps or pyrethrin sprays when necessary.
2. Cutworms
These pests feed on the roots of sunflowers, causing stunted growth and poor yields. They can also sever young seedlings at the base. To manage this pest, use soil insecticides, and remove any plant debris that may harbor the larvae.
By implementing these disease and pest management practices, you can help ensure healthy growth, yields, and quality of your Helianthus ×doronicoides Lam. plants.
