sea holly

I have received today five tubers? at least I think that is what they are. Do I plant them in pots in the greenhouse or straight in the garden.  I live in Wakefield West yorkshire When planting do I plant them horizontal or vertical ( they are about 4" long). I love the look of Sea Holly but have never grown them before.

Roots generally go down.

I've had a selection of perrenials delivered today from Thompson & Morgan. Amongst them were three "Eryngium Planum" bare-root plants (Sea Holly). Like you, I have never grown them before but according to T&M they grow to about 2½' and should be planted about 18" apart. They should be 'planted vertically in relatively moist, well-drained soil in a full sun position'. 'They will tolerate very poor soils'.

Apart from Gardeners World, do always try searching on Google, etc for things you would like to know more about - there's such an abundance of help & knowledge out there. Best of luck with your planting.

Thanks for that recommendation, Verdun. I've not been pleased with the Sea Hollies I've had so far - taken up too much room for their decorative value. I,too, am suspicious of bare root plants, though I understand that those from Toby Buckland are good.

Thaks, Sam. I like miniature versions. I'll have a look.

Eryngium variegatum is quite compact and doesn't fall over but it's not one of the bright blue ones.

I like the biennial Miss Willmott's ghost best, so do the bees.

Thanks, Nutcutlet. Another educational experience!

Eryngiums certainly don't like root disturbance but the method of propagation that is use doesn't stress the plant ( the potted plants are mounted on mounds of sand and left to mature before root cutting are taken from outside the pot, in the sand mounds, which are easy to move).

They produce very long tap roots, like carrots and parsnips, so a deep pot is advisable and they like sharp drainage so put plenty of grit in with your compost. They will happily establish in a pot before you have to worry about planting, although they dont do well if left potted for an eternity.

I moved a Eryngium a few years back which was sickly in the wrong place and it recovered well and is now a monster in the right place, but I wouldn't recommend doing this out of habit. They don't really like it because all their root is in one basket so to speak and yes, they need support topside to reward you with the finest displays.

I am going to plant mine in tall plant pots and leave in the greenhouse until the warmer weather comes. They sound not to difficult to raise in the correct conditions.  i have a sunny poor well drained spot earmarked for them. Some interesting reading in all the comments

Root disturbance is when you rip a plant out of the ground. It's had room to spread and tangle up with other plants underground. A pot is a contained environment, so long as you are gentle, the plant won't even know its gone in the ground.

Thanks Wintersong for the advice I can plant in pots with confidence now