Go to Articles > Herbs (Letter-Letter).
Read through the list on your own. There are many herbs that are used for different purposes, and what you wish to do isn't uncommon. There are many warding herbs and protective herbs. Herbs are like synonyms; you have one word, but you've another that does the same thing. You will likely accomplish the search in the article. You may actually come accross other herbs that draw your intent.
Don't sprinkle poisonous herbs on the floor if it is in the danger of a child or a pet eating them. If you have rodents, as well, don't sprinkle them on the floor anyways, as pests can often carry negative or blocked energy, and simply by stepping on an herb, they can transmit their negative energy.
Consider reading this list; pick out from 2-4 herbs to combine and use with a spell, and should be more affective.
"Cleansing Light" Spell
Arrange a combination of banishing herbs around a candle on a plate. If the herbs are poisonous, it is recommended to use on a disposable cloth or napkin. Stare into the eyes of the candle, and feel the warmth of the candle. Meditate, and visualize a white aura encasing you, and see any negative auras dissolving as soon as it touches with the white aura.
After your meditation, which should be roughly ten minutes or higher, the wax of the candle should be melted and dripping. Combine the herbs in the melted wax, and chant:
"Oh feeble the energies of those gone,
Fond of the elements and my healing songs,
May the sky meet the ground until it is reversed,
Banish the negativity from my life and cleanse the earth."
-Banishing/Cleansing spell from my Spellbook.
However, it may help to create your own spell. Try to memorize them before chanting, so you aren't solely focusing on reading but rather you're focusing on the energies and the spell itself.
~May the Visions of Isis guid you