Allium (Ornamental Onion)

Planting & Care for Alliums

Preparation

• Alliums are best in full sun but will tolerate light shade. Alliums in borders should be positioned where other plants will help to hide their often untidy foliage.
• Smaller species are suitable for rock gardens.
• The soil must be well-drained and should contain plenty of well-decayed manure or compost. Add a dressing of lime to acid soils before planting.
• Flowers in late spring and summer.

Opening Plant Material

• Containers - Completely saturate all container plants by putting in a larger container of water until it stops bubbling, then remove. You’re now ready to plant.
• Scroll down and click on the orange rectangular box "Handling & Planting Guidelines" to see illustrations on how to plant properly. 

Planting containers

• Plant in spring and fall
• Slide plant from pot by tapping on the bottom of the pot.
• With shovel or knife trim bottom 2" off of the root ball for plants in plastic containers.
• Dig a hole no deeper than the depth of the container and 6" or more, making sure it’s wider on the sides.
• Rotate the plant to the proper position. Never lift or move plants by the tops.
• Place the root ball in the hole.
• Notice where the base of the trunk flairs out from the tree. This is called the root flair. This root flair should show when the tree is planted. If necessary, add soil under the ball so the root flair is exposed.
• Place fertilizer packets into the bottom of the hole (if purchased). *Use Our Recommended Fertilizer.
• Backfill the hole with soil, making sure the top of the root ball is visible and slightly higher than the soil around it.
• Firm the soil around the plant. Water well to settle soil around the root ball.

Pruning - After Planting

• Containers - Although it is not essential for containers to be pruned after planting, a light pruning for shape, to remove any broken branches from shipping, or to thin out a heavily branched plant will help in the transplanting process and in the appearance of your new planting.

Pruning - Through-out the Season

• Cut Alliums when about half of the flowers are open.
• Foliage starts to die down before blooming is complete. Cut off the spent flower stems if required.
• Overcrowded clumps can be divided in fall, replanting immediately.

Watering - After Planting

• Plants typically take approximately 6 weeks to establish new roots in your soil. During this period, water plants as often as every 2-4 days at the start and at least a minimum of once per week.
• Beyond the 6 week establishment period, water once per week, unless rains occur.
• Stick your finger into the soil around 3” to check soil moisture.

Watering - Through-out the Season

• After the first season, plants should only be watered during extended periods without rain.
• How do you know if your plants need water? The easiest way to tell is to touch the soil around the roots. If it is moist, there is no need to water. If it is dry, give it a good soaking with the hose end (no nozzle) watering the soil only, not the leaves.
• Stick your finger into the soil around 3” to check soil moisture.

Go to our "Plant Features & Video Tab" for more information & tips on caring and maintaining this plant.