In a knot garden, low-growth plants intertwine in intricate patterns that resemble embroidered stitch work or knots. They were developed during the English Renaissance at the time of Queen Elizabeth I and William Shakespeare. It was popular to adorn garments of that time with intricately woven embroidery. Knot gardens of this time period reflected both formality and elegance. They were almost always shaped like perfect squares, and they were planted with a rich diversity of herbs and flowers. The use of specific plants and patterns to symbolize deeper meanings has always been common in the knot garden, and in its French derivative, the parterre garden.

Because knot gardens were originally meant to be enjoyed from a ground-level perspective, gardeners did not use traditional hedges to define their borders. Square portions of land were parceled off and marked for planting with gravel or sand. Gardeners would then begin by planting whichever herbs or flowers would grow most slowly. These species were intentionally placed very close together so they would intertwine as they grew larger; creating the knotted appearance the garden is named for. Faster growing herb and flower species appropriate to the tastes of the landowner and the aesthetic of the estate would then be added. Both slow-growth and fast growth vegetation required constant water and trimming in order to maintain color, form, and desired height.

Almost any kind of herb or flower may have been found in a knot garden of this time, so long as it looked attractive and proportional to the design, and so long as it contributed a fragrant aroma to its general surroundings. It was not uncommon to mix medicinal and culinary herbs used for folk remedies and spices with floral species renowned for color and intricate form. In almost every case as well, English knot gardens would be landscaped with access points that would let people to stroll only inches away from the heavy concentrations of lush and fragrant vegetation.

Although knot gardens, as all things do, have changed somewhat over the centuries, it is remarkable that the basic concepts of low-level growth, strong fragrant smells, and diverse coloration have remained relatively unchanged. The form has not been abandoned; but rather, expanded. The insistence on perfectly proportional geometry was an aesthetic absolute in the Renaissance that harkened back to the linearity and perfect proportions of Greek and Roman art. Today, we live in a much more subjective and relativistic age where absolutes are questioned. A knot garden, like any other form of art in today's society, may be used to ask a question instead of giving and answer. It may also function more as a complimentary element in a landscape than a primary element.

Knot gardens are often rectangular in design, providing organic linear compliments to stone walls. They are also very popular to plant as surrounding elements around statuary and fountains. In these instances, absolute form gives way to form that follows function and form that connects with other form. This is particularly true when knot gardens are planted around abstract sculptures. Such works of art often benefit more from combination of alternating circular, square, and rectangular trainings than they would from the traditional form of the perfect square. Fountains can be better accentuated—particularly when lighted at night—by a starred pattern, spiral, or circular pattern of greenery and color.

For these and other avant-garde designs, it may also be better to create designs using exotic and non-traditional ground cover species, as well as hedges comprised of boxwoods that designs that better reflect the Existentialism of our era versus the Deism and Theism of the Renaissance.

Ultimately, the degree to which a knot garden conforms to the purist standards of its historical origins or deviates into the uncharted waters of pure subjectivity depends largely on the mindset, tastes, and preferences of the homeowner and the ultimate aesthetic desired for the landscape in general.