A HOUSE should include elements that help create a sense of security and comfort, including in its backyard. Just like how your body needs good back support the same goes for your house.
A sloped backyard can bring bad Feng Shui to a house as it lacks supporting energy.

In traditional Feng Shui, the back of the house is the area of the tortoise, which is one of the four celestial Feng Shui animals. The energy of the tortoise is to create support and stability for the house. Therefore, placing one in your backyard would bring good fortune.
You can apply Feng Shui elements to create beautiful and cohesive backyard landscape designs and bring positive energy into your outdoor living space.
To balance the energy in your backyard, consider adding the following:

ORGANIC WALL
Build an organic wall made from natural materials that blend in with the environment to raise the energy in your backyard. You can do this by putting in place a tall wooden fence or vertical wall garden.
LIGHTS
Install high lights at the end of your sloping backyard to raise the energy level.

ROUND OBJECTS
Round shapes such as a round patio set can evoke a sense of family togetherness and security, thus making a great addition to your yard. The chairs and table do not necessarily have to be big.
LIFE/COLOUR
You can bring life, colour and a sense of stability to your backyard with good landscaping and feng shui products.

WATER
Water is known for its serene and calming effects. You can create a small stream with a waterfall or a koi pond. If space is limited, even a small fountain would do as long as there is running water.

BREATHING SPACE
Just like a cluttered home, a backyard full of items can create a stressful environment. Keep things minimal and do what is really required. You can place small flower pots but keep large trees and plants away from the walls and windows of the house. The more space your yard has, the more positive your yard will feel.