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Landscape lighting design is based on a variety of purposes as outlined below. We usually think of landscape lighting as highlighting the aesthetic aspects of the garden, but there are two other key essential needs for landscape lighting.

Safety lighting – Illuminating driveways, pathways, patios and stairs is as important as turning on a bedroom light so you can see where you are going. Lighting otherwise dark exterior spaces that could cause an accident or injury is a fundamental purpose of outdoor lighting.

Security lighting – Keeping your home safe is not only to keep you safe, but also to keep your home safe and the valuables inside that may be on the mind of a burglar. Spot lights that are motion controlled can detect an intruder and may deter them from trying to break inside. Security lighting however is usually a separate special purpose type of lighting and not typically connected to a garden focused landscape lighting design.

Having worked out the design for your new landscaping, creating a sense of drama and illuminating spaces and focal points is part of the appreciation of the landscape at night. There are certain basis type of lighting that are used:

Area lighting – Fixtures that light up an area such as a patio can be ground level lights or down lights attached to walls or patio covers.

Pathway lighting – Fixtures along a path not only light the way, but show off the linear aspect of the path whether it be straight or curved lines. The series of carefully spaced lights serve to reinforce the “line” which is a fundamental principle in landscape design.

Accent lighting – Architectural features that are illuminated so as to highlight the beauty of the object. This could be the stone veneer of a column, a large boulder, statuary, a specimen tree and many other possibilities. There are many ways accent lighting can be used:

This shadow was created by a setting sun
  • Silhouette lighting – This is a type of lighting that creates a shadow of the object either from backlighting or casting the shadow of the object onto a smooth surface.
  • Pools and Waterfeatures – Water can be illuminated by using direct spot lights, underwater fixtures or even LED strips integrated within a water fall device such as a “sheer descent”.
  • Steps and Seatwalls – There are fixtures called “hardscape” lights that are low profile small strip type fixtures that fit into the caps that cantilever over the face of a wall or bench or even steps.

Design Considerations

The above forms of lighting are for specific purposes and depending on the layout of your garden, fixtures are placed where they are needed. Beyond the functionality of the lighting, the aesthetics must be considered. This is where the fundamentals of design enter the picture. Here are some key elements:

Balance – Think of the landscape as a painting when seen from key vantage points which may be the curb appeal view looking at the landscape from the street or the views from within the home looking out. Lighting should allow your eye to follow the various points of illumination in a balanced manner and not be too concentrated in one area or leaving areas completely dark. Balanced is achieved by careful placement of fixtures as well as balance between path and area lighting vs. up lighting and accent lighting. Balance of lighting is integrated with the composition of the landscape elements.

Other principles of design that can be enhanced by the use of lighting include:

Line

Form

Texture

Color

Proportion

Repetition

Unity

These elements are important to achieve good landscape design. Lighting only emphasizes these principles in the evening and sometimes creating a more intense impact or dramatic effect.

Dealing with Dark Sky Ordinances

Many communities have adopted regulations that control the type of lighting you can install outdoors in order to minimize the light pollution created by uncontrolled lighting. Everybody appreciates a dark sky when you can see the stars on a cloudless evening. The International Dark Sky Association darksky.org has developed principles to achieve dark sky friendly lighting.

  • Minimize the amount of light by both number of fixtures and the wattage of the bulbs.
  • Reduce the area that is being illuminated by pointing lights downward, using glare shield, controlling the beam spread angle. Avoid stray lighting that is beyond the focus of what is intended to be illuminated.
  • Control the duration of how long the lighting is on by the use of timers.
  • Use low wavelength bulbs. In other words, use bulbs that are on the opposite end of the spectrum of a cool or blue wavelength. In LED terms, a lumen output no higher than 3000 Kelvin is preferred. Blue light disrupts our Circadian rhythm which is important for proper sleep cycles.

In terms of energy efficiency and global sustainability, switching to low watt LED bulbs has become a norm. Old halogen bulbs should not be used if you want to save electricity. Some landscape lighting manufactures offer bulbs that can be dimmed using a hand held remote to control individual fixtures instead of simply swapping out the bulb to a higher or lower wattage.

Landscape lighting involves not only using design to achieve a functional yet beautiful impact, but concerns the environmental and social impact on your neighbors and community.

Landscape fabric when used as a weed barrier can cause more problems than it intends to solve

As a professional landscape contractor, I do a lot of remodels and renovation work. Often a homeowner inherits the mistakes the previous owner made including the use of landscape fabric or weed cloth. It may have been the advice of a misinformed maintenance worker or even insisted upon by the homeowner, but in any case there are several pros and cons involved. Being educated about this controversial issue is important for any homeowner considering an upgrade to their existing landscaping involving plants, gravel and irrigation systems.

The Pros – where fabric is useful

1) Prevents weeds from growing from underneath sand set pavers or synthetic grass

2) Reduces weed growth in rip rap lined drainage swales

3) Soil erosion control in difficult sites (where the fabric is also covered with gravel or rip rap)

4) Could be used as an alternative to using chemical based pre emergent herbicides . But this doesn’t really fix the issue of weeds as fabric only delays the need to control weeds until the layer of gravel collects enough debris and forms a soil in which weed seeds that are wind driven find a
place to germinate.

5) Suitable for a minimalist style landscape where mostly Cacti, Agaves and Yuccas are planted and where upgrades and changes are minimal.

The Cons – where fabric creates problems

1) The wrong type of material can deteriorate in UV sunlight. I’ve seen many gardens with exposed black plastic sheeting that over time, looks hideous.

2) Adding new trees and shrubs can be a real mess. Removing the gravel in order to dig the hole, cutting out the fabric is relatively easy, but finding the drip irrigation lines to provide new emitters may be a real headache.

3) Repairing a leak in the irrigation system. Since the drip lines are installed under the fabric, it’s often difficult to pinpoint where a leak is originating.

4) Weed prevention is temporary. Yes, fabric will prevent any weed seeds that are already in the soil from germinating, receiving sunlight in order to grow, but after a few years, enough debris will collect on top of the fabric and along with the gravel cover provide a good soil medium for wind driven seeds to collect and germinate. Clients must be educated that this will happen and be prepared to either remove weeds manually, use a weed killer or pre emergent herbicide.

5) Prevents perennials that reseed and bulbs from populating. Perennials that reseed like poppies and alyssum cannot spread and if that if your intent is to create a perennial garden that thrives and grows from year to year, fabric should not be used.

6) Can be a hazard when used on slopes with the wrong kind of gravel. When used on a sloped area of the yard where perhaps you have a pathway or frequently walk across, roundish types of gravel like crushed granite actually will slide across the fabric as you walk on it, enhancing the
likelihood of slipping and falling.

7) Prevents easy application of fertilizers. Since fabric is placed close to the root ball of the plant when initially planted, its hard to apply fertilizers to the “dripline” of the plant which is where the feeder roots are and continue to form a larger radius as the shrub or tree ages.

8) Prevents earthworms from improving soil structure. Earthworms need organic matter that forms on the soil surface and derives nutrition from the fungi and bacteria that grows on the organic matter. Earthworms also need access to the surface typically after soaking rains since they need a balance of the amount of moisture their skin is exposed to in order to breath.

Not all healthy soils require the presence of earthworms, but their existence does indicate a healthy soil.

Landscape fabric has its uses but is not always the way to go

We recently finished landscaping an entire vacant lot that will be used as an extended backyard from the owner’s main house. He wanted fabric over the whole area which was covered with gravel, shrubs and a waterfeature. It was about 11,000 square feet. Although I hate to use fabric, in this case the soil was so bad in terms of being almost like dust, we had to use fabric so the gravel would not simply disappear into the “soil”.

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