How does your landscape look? It’s time to review the good, the bad and the ugly

This is a great time to look back at how your landscape performed this year. Take a stroll around your yard (between rainstorms). How does your landscape look after the growing season? Which plants grew well? Which ones struggled during the hot summer? What has changed in your yard, or your life, that may mean it’s time to change the landscape?

Landscape changes

As plants grow and mature, you may need to adjust your plantings to give them the room they need. Perhaps it’s time to transplant a shrub from an area that is getting crowded to one that could be filled in more. Perhaps the plants underneath a growing tree are getting less sunlight now, and it’s time to replace them with plants that will better tolerate shade.

Your needs may change over time too. You might like to add screening plants to block new construction next door. You might want to increase the sunlight on your patio or add an outdoor kitchen or lounge area. Perhaps your children need play spaces, or you may want to do more outdoor entertaining.

Consider how you use your yard and what would make it serve you better. Contact us if you’d like to discuss design options. We offer sustainable landscape design and installation to help improve your landscape.

Plants that perform poorly

Do you have any plants that didn’t grow well this year? Perhaps one was spindly, another didn’t flower or one had poor color. Did you see any with fungal disease? Now is the time to review what could have caused the problem.

Is the plant getting too much or too little sunlight? For example, did a nearby plant grow taller, shading the problem plant?

Did it get enough water? Perhaps it is time to update your irrigation system. Drought stress is becoming more common as Seattle’s summers become hotter and drier. Trees are susceptible too. We have seen more drought stress in our clients’ trees in recent years. This is a long-term problem that may eventually kill your trees.

Are your plants getting the right nutrition? If you are signed up for our natural tree and shrub care service, we have been treating your plants over the growing season with nutrients, micronutrients and organic organisms. If not, you may need to take steps to address any deficiencies. An organic mulch, such as compost or arborist chips, will help feed your plants. You may also consider a good organic fertilizer.

How did your lawn do? Our natural lawn care services can help keep your lawn healthy, but proper mowing and watering practices are essential to keep your lawn healthy over the long term. Here are a few quick lawn care tips.

Does the soil have the proper pH? Our Northwest soils tend to be more acidic. Now would be a good time to get a soil test to find out. Here is information on how to test your soil.

Plants that perform too well

Do you have a plant that is taking over an area and crowding out other plants? Consider your options. You could cut it back and wait for it to grow again. You could cut back or remove neighboring plants. Or you could remove the large plant and replace it with something else that is better suited to the location.

Here’s an example. False spirea is a lovely plant, with fernlike leaves, multicolored growth in the spring and downy white blooms later in the year. But it also spreads readily by sending out root suckers to corners far and wide. One gardener called it a “thug.”

Perhaps you planted it in an area that can accommodate a large, readily spreading shrub. If not, you need to consider what steps to take. You could remove the new sprouts each time they come up during the growing season. You could cut the entire plant to the ground occasionally to help keep it under control. You could remove it entirely and replace it with something else that is better behaved.

Invasive and noxious weeds

Now would be a good time to identify any plants that may have “volunteered” in your yard and determine if you want to keep them or remove them. Perhaps the volunteers are noxious weeds.

Noxious weeds are a danger to our environment and the economy. These introduced species cost our region millions of dollars in lost agricultural production, environmental degradation and added maintenance costs. Once invasive plants spread to natural areas, they harm native plants and wildlife and can be impossible to eradicate. State and local laws require many noxious weeds to be controlled.

Examples of common noxious weeds in western Washington

English ivy is a common ornamental, widely used in landscapes. It has been taking over many woodlands and parks in the region. It can cover everything in its reach, crowding out native wildflowers, ferns and tree seedlings. Ivy mats often host pest animals such as the Norway rat. It grows up the trunks of trees, harming the trees’ health and increasing the risk of trees being blown over in windstorms. Property owners are not required to control English ivy. However, the King County Noxious Weed Board strongly encourages control of English ivy where possible and discourages planting it.

Tansy ragwort is an invasive, toxic biennial weed from Europe, most often found in pastures and along roads and trails. It is a host plant to the larvae of the cinnabar moth who like to munch on its leaves. Unfortunately, the moth larvae will eat the weed along with any dusty miller plants you have in the garden. And you will still have the weeds. King County requires landowners to control tansy ragwort on their property. This plant is on the Washington quarantine list (also known as the prohibited plants list). This means it is illegal to buy, sell, transport or offer this plant for sale in the state of Washington.

Purple loosestrife invades lakeshores, wetlands, ponds, and wet pastures and ditches. The magenta flowers grow on tall, narrow spikes from July to October. Unfortunately, some uninformed nurseries still sell it as a garden ornamental. This plant is on the Washington quarantine list, so it is illegal to buy, sell, transport or offer this plant for sale in the state of Washington. King County requires landowners to control purple loosestrife on their property. Please notify the Noxious Weed Board if you see purple loosestrife growing in King County. There is an active and effective biological control program in use against purple loosestrife.

Giant hogweed is a toxic perennial that reaches 15 feet tall. It often grows in urban areas, such as yards and empty lots. In sun, sap that contacts skin can cause severe blisters and even scars. It can crowd out other plants and take over natural areas, especially in moist areas. This plant is difficult to distinguish from the native plant cow parsnip. It would be a good idea to contact the King County noxious weeds program for a positive identification and advice on control methods before removing. King County requires landowners to control giant hogwood on their property. It is also on the Washington quarantine list.

Garlic mustard will be the bane of your garden if not controlled. It is an invasive non-native biennial herb that spreads by seed. It is difficult to control once it has reached a site. Garlic mustard can cross-pollinate or self-pollinate, it has a high seed production rate, it outcompetes native vegetation and it can establish in a relatively stable forest understory. It can grow in dense shade or sunny sites. Plant stands can produce more than 62,000 seeds per square meter to quickly out compete local flora. Garlic mustard also produces chemicals that inhibit the growth of other plants and mychorrizal fungi needed for healthy tree growth and tree seedling survival. King County requires landowners to control garlic mustard on their property. It is also on the Washington quarantine list.

Invasive knotweeds are tall, bamboo-like plants found throughout King County. They were introduced from Asia as ornamentals in the late 1800s. Knotweeds have no natural predators in the US. Growing in large, dense thickets, they reach 4-13 feet tall, with bamboo-like, green-reddish canes and branched clusters of small white to pink flowers. They reproduce mainly vegetatively via extensive roots and rhizomes, a stem fragments. These plants are highly aggressive, clogging waterways, eroding banks and even growing through building foundations. Landowners are not generally required to control invasive knotweed on their property in King County. It is on the Washington quarantine list, so it is illegal to buy, sell, transport or offer this plant for sale in the state of Washington.

Noxious weed resources

The Garden Wise booklet shows noxious weeds and alternative, non-invasive plants for the garden.

The King County noxious weed website has information on identification and control of invasive plants.