Wednesday, June 21, 2023

Managing ornamental grasses

Last week, as I walked through my neighborhood, I snapped a couple photos of a front garden up the street.  The garden, installed last summer, has a simple palette, dominated by Nassella tenuissima (aka Mexican feather grass, fromerly classified as Stipa tenuissima), Senecio serpens (aka blue chalksticks), and white-flowered Lantana with Agaves tucked in here and there.

It's hard to make out many of the Agaves as they're hidden by the masses of feather grass


 

That garden was installed by a professional landscaping firm.  I saw some follow-up activity immediately after the installation but I haven't seen any maintenance activity since.  I wondered what kind of guidance the firm may have provided the homeowners, especially related to controlling the spread of the feather grass, which is known to be invasive in California.

I have the same feather grass in my back garden in several spots.  I love the way it dances in the wind, especially when it's in flower.  I didn't have any significant problems with it the first couple of years but more recently I've learned just how readily it self-seeds.  I've pulled some of it out and I actively monitor and manage the rest.

These are before and after shots of a section of feather grass in my backyard border.  I rake through each clump of grass by hand, pulling out the flowers, as well as any dead material.  It takes hours and, by the time I've finished all of them, it's usually time to take another pass.

Ridding the garden of tiny seedlings is an endless task, made more tedious and time-consuming when they root in between paving stones and amidst groundcovers.  This is a before and after shot of one small area.

 

I've been in spring cleanup mode for the past couple of weeks.  I've cut back all the bloomed-out Aeoniums - well, almost all.  I keep finding more.  I'm pulling gobs of weeds and deadheading spent flowers, as well as cutting back shrubs that may run counter to new regulations for managing fire risk.  (All properties in my high fire risk area are subject to evaluation by the local fire department beginning this month.)  Rain is a double-edged sword, something that's been easy to forget in recent years.  While admiring one of my backyard beds this morning, I realized how dramatically many of the trees I had pruned by professionals in mid-December had fleshed out.  I spent an hour yesterday trimming back the smaller of the two Arbutus 'Marina', only making a small dent in its growth.

View of the bed containing 2 Arbutus 'Marina' (aka strawberry trees).  The smaller tree has just about swallowed up the Melianthus major and has encroached on the surrounding plants, including a Leucadendron 'Jester', a Grevillea 'Ned Kelly' (currently invisible) and a Leucospermum "Royal Hawaiian Brandi'.  I discovered that I had gladiolas and lilies (also almost invisible) growing in there too.

This is a comparison of the smaller Arbutus after its pruning in mid-December and now (after I gave it a light pruning yesterday)

I didn't even try to do anything with the larger Arbutus.  This photo shows it immediately after it was pruned in December and now, 6 months later.
 

 

Work on my cutting garden is ongoing but I expect to have an update on that later this week.  We've had a few sunny days in a row now so there's no time to waste.

The fact that Pipig has voluntarily left her heating pad behind and retreated to her catio is proof that we've had warmer temperatures at last



All material © 2012-2023 by Kris Peterson for Late to the Garden Party

20 comments:

  1. I love Mexican feather grass. Being aware of its robust reseeding I've pulled out all but one and I cut off the "bloom" before it dries out and spread about. If only I had a wild meadow to let it do it's thing... To my eyes, the neighbor's professionally designed front garden is rather uninspiring.
    I'm shocked at how quickly both Arbutus 'Marina' filled in! Has it been different during dryer Springs? One would wish a professional pruning would last a while...
    It is so good of Pipig to land a hand. Or rather a tail. Supervising is hard work.
    Chavli

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    1. I don't think the Arbutus trees have been this beefy even after 12 months of growth, Chavli. I have 4 of these trees, all of which are pruned annually. They're all overgrown now, although the change was most immediately noticeable in the smallest tree as it's now badly encroaching on the surrounding plants. I'm going to have to get the tree-trimming crew in early this year!

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  2. hahaha, Pipig looks very content! I had the feather grass in my slope and finally got rid of it, just too much work to keep it from spreading (for me). I do love how it softly nods in the wind. How much will your neighbor's grass spread throughout the whole hood?! That type of landscape is just not my style, but I know there are fans of it. Sunday I attacked my arbutus, it's not as large as yours there. Thinned it out - the wood is heavy! The rain really did bulk the trees up, your picture of "before" really lets the light through - although both shots are nice.

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    1. I couldn't help wondering how the neighbors nearest to that house are going to feel about the grass next year, tz...I'm eventually going to remove all the feather grass in the beds nearest our house. The grass in the section I photographed next to the dirt path adjacent to the hedge doesn't seem to self-seed as much.

      I have all 4 of my Arbutus pruned hard each year to open up the inner canopy, otherwise they're prone to developing black mildew, probably encouraged by our marine layer. The bigger ones are beyond my capabilities to tackle and, given how large the "small" one has gotten, I'm going to turn that one over to the tree-trimming crew as well.

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  3. I got lost in the first couple of photos before I read your text... what a dreamy look, but yikes! I can imagine it quickly becoming a feather grass monoculture in no time.

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    1. The grass is dreamy when it's waving in the breeze but I don't think you'd put up with it covering up your agaves, Loree ;)

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  4. I’ve stayed away from many grasses because of their invasive tendencies. I bet it’s a rare designer who lets the homeowner know what their responsibilities for a garden will be. Those of us who actually garden have enough trouble figuring this out.

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    1. I can't remember the name of the landscaping firm anymore but I recall that they advertised eco-friendly gardens for our climate. Linda. At the time of its installation I was surprised at just how much Nassella tenuissima they were installing given its invasive status in California.

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  5. Woody plants are a double edged sword. They fit nicely when planted from their containers and you hope they grow quickly to add some presence. However, fast forward and they take over, shading out valuable plants and requiring a ton of pruning maintenance (something that is not easy the older you get or the bigger the plants get). With the increased risk of fire maintenance is even more important.

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    1. I get all 4 Arbutus pruned by a professional service every year and I've never seen them flesh out as quickly as they've done this year but I guess that's what a decent amount of rain can do! I don't trim all our trees every year but I suspect that's what I'll be doing this year - and on an earlier schedule as well!

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  6. If you have a small shrub rake, they make quick work of combing the seed out of clumps of the Nassela. Run the rake from base to top with the tines facing up. It just takes me less than ten minutes to do the patch I have.

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    1. Yes, I need to get myself a small rake like that as pawing through the grass clumps by hand is tedious and usually leaves me with aching arms.

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  7. Hmm..not sure about the design on the House of Nasella. Does it look better in person?

    The Senecio and the Lantana will surely have the Nasella mixed in soon. What a mess that will be. My neighbor has it around their pool and I've been pulling the occasional seedling coming up along the property line. I'm staying alert for seedlings.

    Wow, those Arbutus really liked the rain! The oak out front looks very happy but did not explode with growth.

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    1. I don't care for the House of Nassella myself, HB, although my feelings have less to do with the mass of grass than with the dark gray exterior. I'd have liked to see more succulents in the plant mix too. I noticed some grass seedlings poking up in the Lantana today when I was walking the neighborhood. I expect the owners may find that the landscape they thought would be easy to maintain really isn't going to be that.

      The Arbutus seem to have responded to the rain the most aggressively, although I think the Agonis flexuosa will all need to be pruned hard this year as well. Sadly, my Magnolia still looks stressed to me. It may not be getting what it needs from our irrigation system. I deep watered it last week and I may start doing that once a month this summer.

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  8. I planted one N. tenuissima in the back rock garden a few years ago and didn't find any seedlings for several years. Then, starting 2021, they started popping up here and there. I think it might be time to take it out, but I don't have another short grass to replace it. Now, I cut mine back to the ground in spring and throw the seedheads in the garbage, which probably helps the reseeding, somewhat, but I hate putting organic matter in the garbage. Not comfortable putting in the compost. A local nursery sells Nasella cernua, a west coast native. So far, it has done terribly in my garden - I might try it one more time to see if it was just in a bad spot. Meanwhile, our squirrels did a terrible job of pruning two of our Arbutus this winter. Nipped off every single leafy branch leaving a barren mass of sticks. Amazingly, they are resprouting, but I wouldn't hire the squirrels to prune our Arbutus again. Not sure I have a choice.

    Give Pipig a scritch behind the ear or on the chin for me if she likes that sort of thing.

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    1. Your colder winters may help keep Nassella tenuissima in line, Jerry. Unfortunately, not even the drought does that here. I grow Festuca californica too but it doesn't have the same impact. I've never even seen a squirrel in an Arbutus here! Maybe your squirrels have tougher teeth - or maybe there are just easier things for them to eat here, like my Leucospermum.

      Pipig loves to be scratched behind her ears and is currently demanding a brushing twice a day. She's 16 years old now.

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  9. Invasive grasses are no joke in fire prone areas I've heard. I saw that some areas are using grazing goats and sheep to knock them down.
    Amazing how fast your Arbutus fills in. Makes me glad (in a way) that we have winter to slow things down! Eliza

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    1. Goats are used widely on our peninsula to take care of rampant foliage - I spotted them just a mile away last year clearing a hillside off our main road. Unfortunately, I don't have enough grass for it to be worth their while and I don't think they differentiate well...

      The Arbutus has never filled in so quickly before. I think it's yet another spring rain effect but this one is just a little scary.

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  10. My monster tree is the Brachylaena - but I have a shiny new 'little old lady gardener' chainsaw. When the weather is kind, I will learn to use it. Will still need young strong professionals for the carob.

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