When your preparations have failed you, its time to get creative and work with what you got. In keeping with this theme, I've decided to discuss herbs that can be used for protective magic. Some are offensive, some are defensive, and some are a mixture of the two. There are those in this list that only work (for protection) when combined with other materia magica too. I'll do what I can to summarize a portion of those tidbits here, but rest assured that you're going to have to play with the mixtures you want to use to learn the ins and outs of the spirits behind the flesh. I'll be using both folk names and Latin names where possible.
I am providing this information purely to spark your curiosity and give you some ideas on how to utilize various herbs for magical protection. The rest is all you.
Angelica (Angelica archangelica)
Arrowroot (Maranta arundinacea)
Asafoetida (Ferula asafetida)
Its used frequently in Indian cooking and a little bit goes a long way. Your house will smell terrible after burning it, but if you do go that route chances are nothing spirity will want to remain anywhere near you or the home.
Anise (Pimpinella anisum)
When used in protection, it can be used to force people to process information they may wish to avoid seeing, for example.
There's much, much more to learn about these herbs than what can be cleanly fit into an easy-to-digest blog article. I've studied them for years, both from a medical and a magical point of view, and I'm still learning something new all the time. That being the case, if Herbology is your passion, I thoroughly recommend reading whatever you can on the subject. From a homeopathic standpoint, the data is changing all the time, so be sure to keep up on your reading if you want to use them in a Naturopathic way.
Take care folks,