How many years will these need to be in the greenhouse....

I fear that I have gone and let myself be taken in yet again.......

I ordered a couple of hydrangea 'incrediball' 9cm potted plants, with the big white flower heads, and they arrived last week:





In reality, two 9 cm potted sticks. Only one had signs of life, but I decided to keep them cosy in the greenhouse for a bit, and they now both have a couple of wee green sprouts; however, I am seriously doubting that they will see a planting position this year, and may end up in pots.

Anyone know how vigorous they grow, and what their preferred compost type is (I have MPC and ericaceous to hand)?

Thanks in advance

 

I think they would do better outside all the time, they are tough hardy plants and won't appreciate the heat & low humidity in a greenhouse.

 

They seem to have reasonable root systems, but I am reluctant to put them in a border at the size they are - I tried a small one a couple of years ago and the dog trampled it and killed it within days.

I have some nice big pots, so I will pop them into a couple if those and leave them outside

EDIT - yes, T&M