Species sea holly
blue flowers with blue cones on purple-blue stems

sea holly

Eryngium planum

Also Known As - flat sea holly
Sea holly is an amazing plant species with beautiful, deeply-lobed spiky leaves and lovely bluey-purple thistle-like flowers. It is an excellent choice for providing height and contrast in the garden and looks great when planted in clumps. It is also a great choice for coastal gardens due to its hardiness and drought tolerance. The flower heads are great for cutting and lasting up to 3 weeks in a vase. Best of all, it is attractive to bees, butterflies and other beneficial insects, making it a valuable and beautiful addition to any garden.

Cycle:

Herbaceous Perennial

Watering:

Minimum

Propagation:

Division,Cutting,Seed Propagation,Layering Propagation

Hardiness Zone:

5 - 9

Flowers:

Steel blue Flowers

Sun:

Full sun

Soil:

Well-drained

Fruits:

Fruits Ready In Summer

Growth Rate:

Moderate

Maintenance:

Low

Drought Tolerant:

Yes

Salt Tolerant:

Yes

Thorny:

Yes

watering

Sea holly should be watered regularly to keep the soil moist but not soggy. Water whenever the top inch of soil begins to feel dry to the touch. During the warm summer months, water at least once a week, allowing the soil to dry out slightly between waterings. In the winter, water once every 10 to 14 days. Avoid overhead watering to keep the foliage from becoming too wet, which can attract fungus and pests.

sunlight

Sea holly plants prefer full sun exposure in order to thrive. The ideal amount of sunlight for sea holly is 8 hours a day. Sea holly should get the most amount of sunlight between the hours of 10am and 4pm when the sun's intensity is at its peak. This will give the sea holly the best chance of success and flower production.

pruning

Sea holly (Eryngium planum) should be pruned in early spring, when new growth begins to appear. Pruning should take place when the plant is still young, before it blooms, as too much pruning can cause a decrease in flowering. Prune back damaged or overcrowded stems to a side shoot. Pruning should always be done sparingly; only remove a few stems at a time and reduce the stems to no more than 1 third of their original length. This will help keep the plant healthy and vigorous.

Season

Fall
Winter
Spring
Summer
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Harvest Fruit

The harvesting season for Eryngium planum typically begins in July and ends in September.

Starts Flowering

Sea holly typically starts flowering in July.

Harvest Fruit

The harvesting season for Eryngium planum typically begins in July and ends in September.

Hardiness Map