Some plants, even though not on official do-not-plant or noxious weed lists should be put into a landscape using a bit of caution.
The reason for this is that they tend to take over garden areas rapidly, reseed profusely in unwanted areas and generally outgrow their usefulness. The ones listed below are still attractive plants to use in a landscape, and not officially labeled as noxious weeds, but it is helpful to know some of their not-so-good attributes.
When choosing plants, beware of words to describe them such as vigorous, fast-growing or spreads rapidly. If such descriptions are used, it would be a good idea to do some research on the particular plant before spending money to buy it. Otherwise, you may be faced with a plant that is difficult to keep in bounds.
Aegopodium podagraria (bishop’s weed, goutweed): Unfortunately, this is most commonly described as a rampant and invasive ground cover that spreads by underground rootstocks.
Think carefully before planting it, but also know that it can be kept in check with barriers, in containers or infrequent watering.
Houttuynia cordata: This is a ground cover that grows rapidly in summer, but completely disappears from view in winter. If kept in a moist environment, it can spread quite aggressively, but is better behaved with less moisture. ‘chameleon’ is the most commonly grown and has lovely, multi-colored foliage.
Hypericum calycinum (Aaron’s beard, creeping St. Johnswort): Once this is planted, it is around pretty much forever, so think long and hard before using it.
It spreads rapidly by underground stems, even in poor soil, and will completely take over a garden if allowed to. However, it is very useful when used for erosion control on hillsides and withstands drought conditions.
It can be fairly well contained within a barrier, but has been known to grow under barriers and in cracks in asphalt. If mown down about every two to three years, it can be kept neat looking.
Lysimachia nummularia (creeping Jenny, moneywort): This is a very low-growing and rapidly-spreading ground cover for partly shady areas. It roots pretty much everywhere it touches soil and will fill in quickly, but it is very shallowly rooted and quite easy to remove from garden areas where it may be unwanted. It dies back in the winter, but comes back nicely in the spring, and forms a lovely, chartreuse-colored mat that will choke out weeds. It is a very easy plant to control.
Mentha (mint): First and foremost, do not plant any mint in the ground – keep it contained in a pot, or it will spread everywhere. That said, it is a wonderfully aromatic plant that is useful in cooking or beverages.
Oenothera speciosa (Mexican evening primrose): This plant is useful because it succeeds in places where many other plants will not. When mass planted and in bloom, it looks like a low, pink cloud. However, it spreads by rhizomes and also reseeds quite profusely, so it may pop up in unexpected spots far from its original plot. It makes a wonderful ground cover though for sunny, dry slopes or other difficult-to-plant areas, but just be aware that it can be quite aggressive and even potentially invasive.
Physostegia virginiana (false dragonhead, obedient plant): This plant is very attractive in borders and is easy to grow, but should be used with caution. It spreads very vigorously by rhizomes and if not divided about every 2-3 years, will take over.
Stachys byzantina (lamb’s ears): This plant is popular with children because of its soft, velvet-like texture; they love to “pet” the leaves. It is good used in a border or as a ground cover, but if the flowers are allowed to go to seed, it will pop up in unwanted places. However, stray plants are easy to remove.
It might seem strange that most of the plants listed are ground covers, but spreading plants like ground covers tend to choke out weeds and protect against soil compaction. The plants listed are all ones used in gardens around El Dorado County because they do well here, but a little knowledge about their potential disadvantages will go a long way in helping control them.
Learn all about the “Basics of Composting” at the free Master Gardener Class on Saturday, Oct. 20. The class starts at 9 a.m. and will be held in the Veterans Memorial Building, 130 Placerville Drive in Placerville.
Master Gardeners are available to answer home gardening questions Tuesday through Friday, 9 a.m. to noon by calling 530-621-5512. Walk-ins are welcome. The office is located at 311 Fair Lane in Placerville.
For more information about the public education classes and activities go to the Master Gardener Website at ucanr.edu/sites/EDC_Master_Gardeners/. Sign up to receive the online notices and e-newsletter at ucanr.edu/mgenews/. Master Gardeners is also on Facebook.
Do you have plastic feed sacks or plant containers to recycle? Master Gardeners will gladly take them at the Master Gardener Office. Call before dropping them off and thank you for the donation.