I looked up a few points concerning feminine given names that might help, such as different suffixes like -e, -ka, -ko, etc. but am at a loss as to how to fit them together ("Yomogiko"?) and also how to write this in kana.
Yes we have many common female given names which follow the
kanji representing a plant name + 子(ko) pattern:
- 菊子 (Kikuko, 'chrysanth' + 子)
- 百合子 (Yuriko, 'lily' + 子)
- 松子 (Matsuko, 'pine' + 子)
蓬子 is less common compared to the names above, but it's a possible female given name. It's usually read as ほうこ (Hōko) rather than よもぎこ (Yomogiko). The on-yomi of the kanji 蓬 is ほう (hō), and we usually don't prefer long readings (more than 2 morae) before ko for whatever reason. In addition, some people may feel 蓬 (read as hō) is a "fortunate" kanji related to this legend.
-ka both appear in many female given names, and both have several possible kanji. But I don't know how to form a natural-sounding person name using 蓬 and
-e/-ka. Don't ask me why.