I would like to sew some decorative flowers on my solid color sweaters using plain old needle and thread.

I have seen some readymade cardigans have some beatifully sewn designs on them using a thick thread that looked like wool to me...the design lines pop up.

Can I use just plain wool (used to knit sweaters) with a big needle(is there a name for this needle)

If no,I am looking for any kind of tips and suggestions how I might decorate my garments. If you know of any websites or other resources please share. I could also use appliques, but thought sewing is more satisfying.

Thanks in advance

Amav