Mishnah Parah 11:7: Any hyssop that has a borrowed name is invalid [for sprinkling the ashes of a red heifer, which must be done with a bundle of hyssop]. The [type of hyssop about which one says] "This is hyssop," is valid. Lavender, blue hyssop, Roman hyssop, desert hyssop, are invalid. And [hyssop] of impure trumah is invalid. And one of pure [trumah] should not be sprinkled with [as part of the chatat ritual], but if one did sprinkle [with it, post-facto] it is valid. We do not sprinkle with young [hyssop], and not with buds. [One who was impure and was then sprinkled, as part of the chatat purification ritual, with] young [hyssop] is not liable for [subsequently] entering the temple. Rabbi Eliezer says: [he is] even not [liable for entering the temple if he had been sprinkled using hyssop] buds". Which are young [hyssop]? Stalks that [their flowers] have not matured.

כָּל אֵזוֹב שֶׁיֶּשׁ לוֹ שֵׁם לְוַי, פָּסוּל. אֵזוֹב זֶה, כָּשֵׁר. אֵזוֹב יָוָן, אֵזוֹב כּוֹחֲלִית, אֵזוֹב רוֹמִי, אֵזוֹב מִדְבָּרִי, פָּסוּל. וְשֶׁל תְּרוּמָה טְמֵאָה, פָּסוּל. וְשֶׁל טְהוֹרָה, לֹא יַזֶּה. וְאִם הִזָּה, כָּשֵׁר. אֵין מַזִּין לֹא בְיוֹנְקוֹת, וְלֹא בִתְמָרוֹת. אֵין חַיָּבִין עַל הַיּוֹנְקוֹת עַל בִּיאַת הַמִּקְדָּשׁ. רַבִּי אֱלִיעֶזֶר אוֹמֵר, אַף לֹא עַל הַתְּמָרוֹת. אֵלּוּ הֵן הַיּוֹנְקוֹת, גִּבְעוֹלִין שֶׁלֹּא גָמָלוּ:

Mishnah Parah 11:8: Hyssop with which one sprinkled [during the chatat ritual] is valid for use in purifying the metzora [one with a skin illness which renders him impure, and whose purification ritual involves hyssop]. If one picked it [the hyssop] as wood, and liquids fell on it, one may dry it and it is valid [for sprinkling with]. If one picked it as food and liquids fell on it, even if one dried it, it is invalid [for sprinkling]. If one picked it for use for the chatat ritual, it is as though it were picked as food, according to Rabbi Meir. Rabbi Yehuda and Rabbi Yose and Rabbi Shimon say: [it is] as though it were picked as wood.

אֵזוֹב שֶׁהִזָּה בוֹ, כָּשֵׁר לְטַהֵר בּוֹ אֶת הַמְּצֹרָע. לִקְּטוֹ לְעֵצִים וְנָפְלוּ עָלָיו מַשְׁקִין, מְנַגְּבוֹ וְהוּא כָשֵׁר. לִקְּטוֹ לְאֳכָלִין וְנָפְלוּ עָלָיו מַשְׁקִין, אַף עַל פִּי שֶׁנִּגְּבוֹ, פָּסוּל. לִקְּטוֹ לְחַטָּאת, כִּמְלֻקָּט לְאֳכָלִין, דִּבְרֵי רַבִּי מֵאִיר. רַבִּי יְהוּדָה וְרַבִּי יוֹסֵי וְרַבִּי שִׁמְעוֹן אוֹמְרִים, כִּמְלֻקָּט לְעֵצִים: