Primaveral: adjective, meaning of, relating to, or taking place in early spring (as in, for example, the primaveral blossoming of the Cherry plum tree in my photo).
According to the Oxford Dictionary, the word appeared in the English language in the early 19th century, having come possibly from the Catalan primavera, the Spanish primavera, the Portuguese primavera, or the Italian primavera, which all mean ‘springtime’. And those words probably came from the Latin prīmum vēr, meaning first or earliest spring.