Archive for Noxious weed list

Resistance is Futile-Plants that take over your landscape

Resistance is Futile-Plants that take over your landscape.

 

This blog is about attractive plants that take over your landscape.  They are tempting and for sale at most garden centers.

Star Trek The Next Generation came out 20+ years ago but I was busy building my landscape design practice and raising a stepdaughter so I missed the whole thing.

Maybe I’m just going to seed as I recently watched all seven seasons in short order. I encountered the Borg and was impressed with their ability to take over a universe. The Borg remind me of certain plants that will happily assimilate your entire garden and need to be avoided. 

Here’s a list of plants that are as devastating as the Borg and good at propagating their own kind without any assistance. They have an aggressive spreading growth habit and yet they are still sold at most nurseries and garden centers in spite of their thuggish nature. Be warned.

Foliage of houttynia 'Chamelon', is an aggressive spreader in Portland Oregon gardens.

Houttuynia cordata ‘Chameleon’ Photo Source

Here is a beauty of a beast: Houttuynia

Houttuynia cordata ‘Chameleon’ –  I’ve never known anyone who (once it was planted ever managed to get rid of it. It is famous for aggressive roots that will grow through other plants and overpower them. It can seed although it hasn’t in any of my clients gardens because I never use it.  Look at how cute the variegated leaf  is!

Aggressive Japanese Bloodgrass in Portlands' Raleigh Hills residential landscape design

Japanese Bloodgrass, Imperata cylindrica ‘Red Baron’, can spread indefinitely

Japanese Bloodgrass Spreads

Imperata cylindrica ‘Red Baron’ or ‘Rubra’- Japanese blood grass is a spreader but it can be dug out and eventually (as in years of work later) be banished but don’t sacrifice your time to this plant…you will be sorry!!

Aggressive Ribbon Grass in NW Portland parking lot is well contained by boulders.

Ribbon Grass, Phalaris arundinacea

Ribbon Grass is on the Fence

Ribbon Grass, Phalaris arundinacea, is a plant that can be very difficult to eradicate but if a designer suggests it for a contained area that doesn’t mean they are a newbie.  It is planted in a parking lot that I frequent. It’s been trapped there over 9 years and has not escaped. I myself have never used it in a design but it is very very low maintenance.   Here is an article regarding success in killing the ribbon grass. 

Front yard of North Portland Row House is lost to Aspens aggressive growth habit.

This stand of Aspens (Populus tremuloides) started out as one trunk!

Aspen Trees

Aspen trees, Populus tremuloides, are beautiful in a forest but not good for tiny city plotsOne tree will become many and fill your soil space with invasive roots that lift walkways, invade foundations and water lines and leave companion plants with no water or nutrition. See this great article from designer pal Beth Goodnight regarding the evils of aspen and some alternative suggestions.

Keep Mint in a Pot

If mint gets away from you – you will never get rid of it. Some people plant it in a pot and keep it on a concrete patio. The roots can escape from the pot and once it spreads in your soil you will have it forever so I never set my pot of mint into a planting bed. I like having mint for soups but it is strictly a container plant. 

Japanese Anemone in Portlands' Grant Park neighborhood in low maintenance residential garden design.

Japanese Anemone is beautiful but travels fast

Japanese Anemone and Bishops Weed in the Right Spot Only

Japanese anemone, Anemone sp., should only be used by experts. This one is very very seductive and over the top beautiful. It travels by root which is the problem. I like to use it in very low maintenance planting plans/landscape designs and in parking strips where it is easily contained. It doesn’t seem to invade the lawn so I’ve used it in plant borders too.

Bishops weed, Aegopodium podagraria, should be planted by people who know exactly what they are in for. It can be contained in the parking strip or a low maintenance planting where you have nothing but shrubs. Large shrubs with bishops weed as a ground cover can be a functional landscape choice. If I use it I have a rule:  You are not allowed to ever give a start of it to a friend.      

There are, of course, many plants besides my short list that should be avoided or used with caution. These plants are the stars of this blog because they are so attractive, tempting and readily available at your local garden center.

Ornamental Grass in the Landscape

Low Maintenance Grass for Your Landscape Design

Low maintenance xeriscape landscape design with good grasses.

Good grass like Pennisetum alopecuroides ‘Little Bunny – Dwarf Fountain Grass is drought tolerant along with Stepable Thymus praecox ‘Elfin Pink, a nearly flat Thyme groundcover.

Designers love to use ornamental grasses to add structure and seasonal interest. They have instant appeal and we designers are suckers for plants that soften pathways and make a dramatic statement.  They are a staple in modern landscape style. However, grasses have a bad reputation.

Grasses for those Who Hate Weeding

I’ve had to reassure more than one new client the grasses I use don’t spread or reseed. My years of experience with plants means I’m slow to use the untested new plants, including grasses.  I’ve seen too many new industry introductions (plants) that looked like a good thing turn into thugs after a few years in a garden. Most of my clients say weeding is the worst of the outdoor chores so I shun plants with potential for adding weeding to the maintenance list.

Researching New Plant Material

 Low maintenance landscape design using Salvia Raspberry Delight Bouteloua BlondeAmbition

Salvia ‘Raspberry Delight’ with Good Grass Bouteloua gracilis ‘Blonde Ambition’ Photo credit High Country Gardens

I’m writing this blog during my winter break when I research new plants and prepare for another busy year designing Portland gardens. I confess to being a teeny bit bored with my tried and true grasses.

I was quizzing a couple of my landscape designer buddies about new ornamental grasses.  I discovered they are sticking to the tried and true grasses and not using any new risky plants in their designs either. Here I was thinking they might be experimenting with new plants and that I was getting behind! Nope they are nervous nellies about using an unknown too.  We see what happens when a client buys some cute new plant only to have it take up a forever place all over the property…

Beautiful Bad Grass? – Mexican Feather Grass

Edited Mexican Feather Grass

Beautiful bad grass – Mexican Feather Grass Stipa tenuissima. Photo credit Proven Winners

Designers are concerned about grasses that seed and make weed problems for our clients.  The Mexican Feather (Stipa tenuissima) Grasses are highly desirable because they are so finely textured the slightest breeze sends them into graceful sway. They are over the top beautiful! They can seed some or a lot and they are the darlings for xeriscape or low water gardens.  This grass is perfect for many dry and hot natural areas in California and (so naturally enough) it is on their noxious weed list.

This Bad Grass is so good in Modern Design

I don’t use Mexican Feather Grass but I have wanted to…they are unique, beautifully blowzy and are a stunner for modern minimalist designs.   I have a local gardener pal who has them in her large Portland modern garden design to fantastic effect. People who are gardeners with a capital ‘G’ may keep up with weeding out the unwanted grass seedlings. Still, all it would take is a distraction, health problem, or too much overtime, and this grass would be seeding into a new planting bed at your property and then your neighbors! Part of hiring an experienced designer is the safety margin we bring to the design process.

Beautiful Good Grass: Blue Grama ‘Blonde Ambition’ 

Low maintenance plant Blonde Ambition for Portland landscape design.

Bouteloua Gracilis or Blue Grama Grass ‘Blonde Ambition’ moves in the breeze like living art.

Bouteloua gracilis or Blue Grama Grass ‘Blonde Ambition’ relieves my boredom in a flash and is a great substitute for the wildly popular Mexican Feather Grass. Discovered by David Salman of High Country Gardens, this plant has all the drama of Mexican Feather Grass but won’t seed around.   It’s very dramatic looking with a flower head that juts to one side like an eyebrow.  It’s evergreen and moves beautifully in the breeze so it’s not just a plant, it’s living art.

A Great Drought Tolerant Grass: ‘Shenandoah’ Switch Grass

Switch Grass Panicum virgatum ‘Shenandoah’ is a colorful Good Grass.

Another great grass for our Pacific Northwest landscapes is Switch Grass. Although there are many varieties,  Panicum virgatum ‘Shenandoah’ is a lot of fun…for a grass. It emerges in the green tones, then quickly adds red coloring throughout the summer. The tiny garnet seeds are nice and airy, followed by a great fall show. To top it off, this grass is well-behaved and drought tolerant once established.

Low Maintenance Landscape

Grasses can be very useful additions to a low maintenance landscape. For the ones listed here, cut the plant down in February to a few inches tall, scuff the crown of the plant and pull away any loose grass stalks from the crown.  It will thrive in a lighter soil mix with lots of sun.  It prefers no fertilizer, low water and can be fully drought tolerant after established.  To kill these grasses, plant them in heavy clay and over water them.  I’m excited about adding these good grass to xeriscaping planting plans in the coming year.

If you are looking for low maintenance landscape design, contact me to learn more about grasses for your Portland area garden.