निम्बू Lemon Tree
If you have little land @ home or shared land among planned neighborhood, one tree I suggest for plantation if Nimbu (Lemon) tree. It is truly a boon for not only its fruits but also for its presence in the garden. It will keep certain types of insects and bacteria away from your local environment. Odor of lemon keeps mosquito at bay.
Benefits of lemons:
Saves you from food poisoning
Both Vibrio parahaemolyticus and Salmonella enterica (two common causes of food poisoning) were all reduced to below detection limits through the addition of lime extract.
Saves you from Maleria
“lime juice when used with the appropriate antimalarial may enhance malaria parasite clearance especially in those with uncomplicated malaria.” 
Lime has been found to enhance the disinfection of water, by both killing norovirus as well as Escherichia coli. Lime has also been found to kill the cholera pathogen, which is believed to affect 3–5 million people and causes 100,000–130,000 deaths a year as of 2010.
Pancreatic cancer is a notoriously difficult to treat type of cancer. Lime juice was found to induce programmed cell death in pancreatic cancer cells. 
Besides, lemon helps a lot in dental care, skin care and Gut care (Pickles).
We have 1 adult tree and 2 growing ones. Picture is of the 10 years old lemon tree in our backyard. It gives us enough lemons for regular use. Indebted to this tree! (First Photo)
As per Ayurveda, Lemon reduces aggravated Pitta. Will share this perspective in separate post.
Replace your lawns with trees! Utilize common plot space by planting more and more fruitful trees!