It doesn't work like that, guest. It's more a case of the maturity of them, and also what species they are. Also - some shrubs /trees may have been forced into flower by the Nursery, and then 'sulk' when replanted in your garden, so they take a few seasons to settle down before flowering again.

There are some that have been grafted onto more reliable rootstock, too. A good example of this is a Wisteria. If you bought an ungrafted plant, it might take several years to flower - or never!

You need to buy from a reputable source - in the case of roses, choose a 'name' like Peter Beales, David Austin, Fry's etc. Then you can be pretty sure that your new rose will perform well.

I have seen modern rose seedlings flowering when only 20 cm tall, though some shrub rose varieties are very shy to bloom the first year.

I bet you didn't count the leaves, though, Tug! ;-)

Nope!

LOL.