You could force them to flower early by giving them a chilling period earlier than usual, by putting them in the fridge.

One batch could be put in two weeks earlier than the second batch. The last lot of tulips could be left to get their chilling from the garden, rather than the fridge. I'm guessing that you live in a climate that gets cold winters.

I don't think you would have much luck in trying to get them to flower later than what they would normally want to flower. Shade might help but that would be hard to have them first in some shade and anyway, they don't really want it. It gets complicated and messy and seems too hard to bother about unless you want to experiment for a bit of fun (with a quarter of your entire batch).

Good luck.

Thanks. I do not have a spare fridge to store the bulbs.

I may try to plant some at 6 inches deep, instead of 4 -5 inches. The problem is I have a hard soil.

Here in Australia we plant tulips in April - May. So I figure that you need to plant yours in October - November. So you have time to wait for soft, slow rain to soften the soil.

(Don't forget to allow the soil to drain for a day or two after good soft rain so that you are working in damp, not wet soil. Working wet soil is hard work and is not good for the soil or you.)

Good luck. I hope the deeper planting helps.

You could also mail order early and late bulbs. Some place like Brent and Becky's or John Scheepers will have a wider range of choices as to bloom time.