Our Plant Health Team weeds each of our 22 million plants by hand at our four growing locations, allowing us to reduce the amount of herbicides required. Hand weeding is a labor intensive process, but one that is safer for the environment.
Another way we combat weed growth is by using organic mulches, which block sunlight and the weeds’ ability to flourish.
In the early 1990s, we began incorporating slow-release fertilizer into the soil, which reduced the amount of nitrogen fertilizer – a source of greenhouse emissions – by 75 percent.
We carefully track the nutritional status of our plants to avoid over-application of fertilizers, which is wasteful and harmful to the environment. By carefully monitoring fertility levels in the soil, we have been able to cut the amount of nitrogen fertilizer applied through the irrigation water by an additional 50%.
When pesticide applications are necessary, only the least harmful pesticides are used. Biorational products – pesticides of natural origin that have limited or no adverse effects on the environment or beneficial organisms – are used whenever possible.
Our Integrated Pest Management program relies on predatory insects to reduce pests, with weekly applications of various beneficial insects and bacteria, such as beneficial spider mites to treat pest spider mites and whitefly, beneficial nematodes for control of insects, beneficial fungi or bacteria for the control of various diseases and insects and beneficial wasps to control aphids and red scale.
One key focus of our new plant introductions is to find plants with a high degree of natural pest and disease resistance, thereby reducing the need for pesticide application both at our nursery and in the home landscape.
We add mycorrhizae to all our plants. Mycorrhizae are a group of beneficial organisms that grow along the roots of host plants, enlarging the roots’ naturally-occurring surface-absorbing capacity by as much as 100 times, making the plant much more efficient in the uptake of nutrients and water. Mycorrhizae help to reduce transplant shock, stress from drought, soil-borne diseases, water usage and the reliance on fertilizers.
Mycorrhizae are found in nature, but are very fragile. By disturbing the ground, we destroy the web of mycorrhizae that lies just beneath the surface. Basic building construction can destroy 20,000 to 40,000 years of soil development at one time. Fortunately, mycorrhizae can be reintroduced and begin to enhance the soil rather quickly. As Monrovia plants are added to the garden, the mycorrhizae in our soil will spread to other areas, benefiting your entire landscape.
When non-native plants with a vigorous growth habit spread naturally to surrounding natural habitats, we call them invasive. Invasive plants can take over the natural environment. But an invasive plant in one state might be perfectly fine in another part of the country. That’s what makes the threat of invasive plants so challenging. When people move to a new state, they may want to grow plants that they enjoyed in another part of the country – and don’t think to check if that plant is invasive.
We are keenly aware of the problem of invasive plants and we do not sell plants in a region if they are considered invasive. Some varieties we have stopped growing entirely because they became invasive in more and more regions. And before we introduce a new plant variety, it is scrutinized for potential invasiveness.
Monrovia is working with other growers and horticulture professionals to adopt best practices to reduce the spread of invasive plants. What can you do? Before you plant, check your state’s invasive plant list.