5 bulbs.
 
A peony style double early tulip.  Cheerful, bright orange tulip that echoes the two tone feathering of Prinses Irene.  Pair this with the double late peony style tulip Orange Princess.
 
All Tulips need a sunny spot, preferably an area of the garden that gets full sun, i.e. 6 hours plus.  Tulips will do well in their first year if they get less than this but rely on a good level of sunlight as flowering finishes and the leaves absorb light to create energy for the bulb for the following year. 
 
All bulbs require good drainage and we strongly recommend adding grit, gravel or sand to planting holes to aid drainage.   Bulbs will rot if they are waterlogged.    If you garden on very heavy clay soil, use tulips in pots as they will not perform well in clay soil.