Swan plants are a favoured host plant for butterflies, especially Monarchs. By cultivating swan plants, you can create a nurturing environment, attracting butterflies to lay their eggs and providing a safe haven for caterpillars to grow and transform into beautiful butterflies.
Planting Calendar
Swan plants are best planted in spring and summer.
Prepare
Position
Swan plants do best when planted in full sun with some protection form strong winds. They can be grown in the ground and also do well when grown in containers.
Soil
When planted into the ground swan plants prefer a free-draining soil that is rich in organic matter. To improve the organic content in your soil, break up the soil and add Kings Compost and Kings Sheep Pellets then mix together well. When growing in containers, plant into Kings Container mix. This mix contains Saturaid, which helps with moisture retention in the soil.
Plant
When planting into the ground, gently tap the plant out of its pot. Dig a hole twice the depth and width of the plant’s root ball. Mix Kings Compost into your existing soil at a 50/50 ratio, add Kings Sheep Pellets, then mix together. Backfill the hole with this soil, so that when planted the top of the plant’s roots sit level with the surrounding ground. Firm the soil down gently and water in well with Aquaticus Organic Garden Booster. In heavier clay soils, where drainage is likely to be an issue, plant onto a raised mound and sprinkle Gypsum Clay Breaker into the bottom of the hole, this helps slowly condition the soil and help to break down the clay. When planting into containers plant into Kings Container Mix, as this has water retention crystals in it, which will help in keeping the soil moist.
Care
Watering
Water well during the hotter months of the year, aiming to keep the soil moist. Water slowly, allowing the water to sink down into the roots, rather than just allowing it to run off the top of the surface of the soil.
Feeding
When planted in the ground liquid feed every month with Aquaticus Organic Garden Booster, from Spring through to the end of Autumn, this encourages root growth and increases the microbial activity in the soil. Monthly applications of Kings Sheep Pellets will help with soil conditioning and plant health.
Protecting
The absence of caterpillars is most likely caused by predation. The main predators of monarch caterpillars are wasps. Aphids are also a problem for the plant but do not harm the caterpillar. Spraying is not an option as any insecticide will kill the caterpillars as well. Use you fingers to squash the aphids or gently hose off the plant. Wasps are more difficult to control, check around your garden for wasp nests and spray at night with wasp killer, place wasp traps around the garden which will trap the wasps.
Mulching
Mulch around the base of the plants (making sure it is not in direct contact with the trunk) with Living Earth More than Mulch. Mulching helps to reduce weeds as well as aiding the soil to lock moisture in the ground.
Spraying
Do not spray swan plants for insect pests as it will also kill any caterpillars.
Pruning
Once your plants are 30cm high pinch out the growing tip of the plant. This will encourage side shoots (laterals) to grow, making a bigger bushier plant with more leaves for those hungry caterpillars. Repeat again as the plant grows.
Beginner Tip
Seeds need soil temperatures of 21–24°C to germinate, so plant in seed trays undercover or in trays in a sheltered place outside if it is warm enough. Transplant into the ground before they are too big (under 20cm) as the roots don’t like to be disturbed.
Expert Tip
Relocating caterpillars from one plant to another should be done without handling the caterpillar. Either pick the leaf the caterpillar is on and place it next to the new plant and let the caterpillar move in its own time, or put the new plant next to the existing and the caterpillar will relocate when it is ready. Do not handle the caterpillar as this can harm them.
Tip
Plant some swan plants in the garden to feed the caterpillars. Grow some where they can be covered with Bug Net. This allows the plants to grow bigger providing a on going supply of fresh food.
Frequently Asked Questions
What are Swan Plants?
Swan plants, also known as balloon plants or Gomphocarpus physocarpus, are a type of milkweed native to Africa, popular in Auckland for attracting monarch butterflies.
How do I plant Swan Plants?
When planting into the ground, gently tap the plant out of its pot. Dig a hole twice the depth and width of the plant’s root ball. Mix Kings Compost into your existing soil at a 50/50 ratio, add Kings Sheep Pellets, then mix together. Backfill the hole with this soil, so that when planted the top of the plant’s roots sit level with the surrounding ground. Firm the soil down gently and water in well with Aquaticus Organic Garden Booster. In heavier clay soils, where drainage is likely to be an issue, plant onto a raised mound and sprinkle Gypsum Clay Breaker into the bottom of the hole, this helps slowly condition the soil and help to break down the clay. When planting into containers plant into Kings Container Mix, as this has water retention crystals in it, which will help in keeping the soil moist.
When should I plant Swan Plants?
The best time to plant Swan Plants is in spring after the last frost, as they thrive in warmer temperatures.
How often should I water Swan Plants?
Water well during the hotter months of the year, aiming to keep the soil moist. Water slowly, allowing the water to sink down into the roots, rather than just allowing it to run off the top of the surface of the soil.
How do I attract butterflies with Swan Plants?
Swan Plants are excellent for attracting monarch butterflies. Plant them in groups to provide ample food for caterpillars.