to grow - present participle

Heill!
Can someone assist or advise me on a VERB matter?
What is the Present Participle of GRÓA (to grow)?
This is what I've found so far... but I cannot for the life of me figure out the PresPart. Is it
possibly: GRÓIN?

INDIC.Pres. Sing. grœ-r (grows) Sing. græ (grœ) ?
Plur. gró-a (grow)
Pret. Sing. grö-ri (grew)
gre-ri

IMPERAT. gró (grow)

SUBJ. Pret. Sing. grö-ri (growth)

INFIN. gró-a (to grow)

PART. Pass. gró-inn (grown)

Part: Growing Past Part: Grown

Any help of direction would be appreciated.
Ves heill,
Sean