If a trait is recessive, the only way for it to show as the phenotype is if the genotype has 2 recessive alleles (homozygous recessive).
If a trait is dominant, the allele would take over in the presence of a recessive one (heterozygous).
So, if pink is recessive the plant must have 2 of the same recessive alleles to make a pink flower.
Hope that helps!