Add texture to the garden with these stunning thistlelike perennials.
Most gardeners don’t have good things to say about thistles.
These extremely tough plants thrive even when neglected.
Sea holly can grow in some genuinely tricky situations, such as difficult-to-deal-with gravel.
With their spiny foliage and flowers, sea holly plants make a dramatic companion to many garden plants.
Where to Plant Sea Holly
Choose a full sun location withwell-draining soilfor sea holly.
They can tolerate poor soil but not wet soil.
Plant several together in acottage garden settingor add them to a rock garden.
They will germinate the following spring after aperiod of cold stratificationbut likely won’t bloom the first year.
Sea holly seeds can be started indoors, but they need to go through a cold period.
Put them in a warm area and expect germination in 7-10 days.
Allow them to grow in their containers for a few weeks until the seedlings are robust.
Harden the plants off beforetransplanting them to the garden.
Plant sea holly transplants in the spring after all danger of frost has passed.
Put them in holes a few inches wider and only slightly deeper than their rootballs.
Choose their permanent location carefully because sea holly doesn’t handle being transplanted well.
Sea Holly Care Tips
Sea holly plants are relatively care-free after they are established.
Light
verify to give sea hollyfull sun.
In part sun, the plants will flop and have less-than-ideal coloring.
They will also bloom more sparsely and lose some of their spiky appeal.
Soil and Water
Sea holly plants favor dry, poor soil.
Their one weakness istoo much water.
it’s possible for you to quickly kill sea holly with soil that stays too wet.
Don’t water established plants at all except during an extended drought.
With sea holly, stay away from soil with lots of organic matter.
It encourages lush, soft growth and causes sea holly to grow and flop over.
Temperature and Humidity
This plant doesn’t do well in high temperatures and high humidity.
It grows best at 55F-60F, although it will tolerate somewhat higher temperatures for a short while.
Fertilizer
Don’t fertilize sea holly.
Fertile soil can cause the plant to sprawl.
Pruning
Deadheading spent bloomsextends the blooming season.
Potting and Repotting Sea Holly
Sea holly is anexcellent container plant.
Choose a container with good drainage and fill it with sandy soil.
Sea holly doesn’t transplant well, so repotting may not be successful.
Pests and Problems
Planting sea holly in wet soil leaves it vulnerable to crown rot andpowdery mildew.
Improve the soil drainage and air circulation around the plants to prevent these afflictions.
Occasionally, the plants attract slugs.
Replant the parent plant in its original location.
Seed: In the fall, prepare a propagation bed withsand, vermiculite, or perlite.
Mark the area and then sow the seeds across the surface of the bed.
Cover them with a scant covering of the planting medium.
They need sun to germinate.
Leave them there until the following spring, at which point, water them to start the germination process.
After several weeks, shake the bag to loosen the seeds.
Store them in a dry place until planting time in spring or fall.
The plant stands 2-3 feet tall in zones 4-8.
The plant produces many tightly packed, glittering steel-blue flowers throughout the summer growing season.
It matures quickly and stands 2-3 feet tall with a 1-2 foot spread.
They’re nothing short of stunning next to white or blue flowers.
They thrive in hot, dry, sunny conditions like a south-facing slope.
A number spread rapidly to the point of being aggressive.
Countless new hybrids are released yearly in addition to the tens of thousands of cultivars already registered.
Yarrow
Yarrowis one of those plants that give a wildflower look to any garden.
It is a native plant and easy to care for.
Its colorful, flat-top blooms rise above clusters of ferny foliage.
If deadheaded after its first flush of blooms fades, yarrow will rebloom.
If left to dry on the plant, flower clusters of some types provide winter interest.
Flowers of yarrow are excellent in fresh or dried arrangements.
It contains mostly long-lasting plants that require minimal maintenance year after year.
Frequently Asked Questions
Unless you deadhead the plant, it will reseed itself.
You might find plenty of volunteer seedlings around the garden.
The plant is deer-resistant and rabbit-resistant.
The sharp spikes on the scented blooms and foliage make it undesirable to large animals.
However, it is highly attractive to birds, butterflies, and moths.
Despite its self-seeding properties, sea holly is not considered an invasive plant.
