the Fatwa Department Research Committee - chaired by Sheikh `Abd al-Wahhâb al-Turayrî
The important hadîth for this question are as follows:
Our Prophet (peace be upon him) said: “Never does a Muslim a plants a tree, but that he earns the reward of charity because what is eaten from it; and likewise what is stolen from it, what the wild beasts eat out of it, what the birds eat out of it, and what people take from it is charity for him.” [Sahîh Muslim (1552)]
The Prophet (peace be upon him) said: “Never does a Muslim a plant a tree or sow a crop and a bird, human being, or beast eats from it without earning the reward of charity.” [Sahîh al-Bukhârî (2320) and Sahîh Muslim (1553)]
Allah knows best about how this might apply to potted houseplants which are merely kept in the home for decoration and household purposes. Houseplants do not provide the types of general benefit mentioned in the hadith as being the reasons for the reward. The hadîth describes the reward for planting a tree to be that of charity. The hadîth goes on to describe the charity as being realized through the food the tree provides for humans and animals.
We might extend the meaning of the hadîth by analogy to other benefits that plants provide to people, animals and the environment. For instance, trees provide shade along the road and contribute to the beauty of the urban environment. These are important benefits that are enjoyed by the general public. Likewise, trees provide habitation and shelter for birds and many other animals.
However, similar benefits to the public that can be likened to charity are not really seen in the houseplants a person keeps at home for beatification, fresh air, and other purely personal reasons. Therefore, we cannot easily extend the hadîth’s meaning to such plants.
However, we cannot rule out a reward for taking care of such plants.
If the houseplant dies through no fault or negligence of the owner, then there is, of course, no sin upon the owner for its death.
And Allah knows best.
Source: Islam Today