Planting depth questions.

2 years ago

Our new house has beds landscaped with rock. The layer of rock is several inches thick. When planting bulbs in them do I account for the layer of rock in the planting depth? Or do I plant the correct amount of inches into the soil, then cover with rocks?

I’d also like some information on the importance of planting depth. What happens when bulbs are planted too shallow/deep? How precise does one need to be?

Here is a picture of the rocks I’m planting in.

Thanks in advance!

Featured Answer

gardengal48 (PNW Z8/9)

2 years ago

While a river rock mulch can be fine in some situations - mostly with very xeric plantings - it is rarely recommended for your typical temperate landscaping. And its primary disadvantage is that it does nothing to improve or enhance the soil like any kind of organic mulch does. And since rock mulches always tend to come with a landscape fabric underlayment, that is just a double whammy.....in a negative way :-)

I agree to get rid of the rocks and fabric where you intend to plant the bulbs. Personally, I:d get rid of both altogether but that is a personal choice.

And planting depth for daffodils is not critical. Narcissus bulbs have what are known as contractile roots or roots that have the ability to pull the bubs down to the appropriate depth for their optimum growth. Lilies and hyacinths and some tulip species also have this attribute

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Comments (12)

mybrownthumbz6
Original Author
2 years ago
I’m planting ’Cheerfullness’ daffodils if that matters.
Tiffany, purpleinopp Z8b Opp, AL
2 years ago
Those are beautiful rocks! But Daffs will need a spot without rocks over them. Some might be able to get through, but I wouldn't spend $ on Daffs & then cover them with rocks. Is there plastic or landscape fabric under the rocks?
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mybrownthumbz6
Original Author
2 years ago
Thank you! There is landscape fabric underneath the rocks. My plan was to cut a hole out of the fabric to access the soil. I tried just clearing the rock and augering into it once, but that was a total failure-- good way to break your wrist! I should have come here and asked first because I already added some muscari and anemone in another spot.
callirhoe123
2 years ago
If I were you, I would remove the rocks and landscape fabric, then plant your bulbs and mulch. Much less struggle and a better result come spring.
mybrownthumbz6
Original Author
2 years ago
It’s an undertaking I’m not looking forward to, but it’s in the grand plan.
Tiffany, purpleinopp Z8b Opp, AL
2 years ago
So sorry you'll need to do that before gardening in this area, but I agree that you will. I knew there would be one or the other under there. Are there trees above or adjacent to this spot that drop seeds?

You might find someone who would want the rocks if you do not have anywhere to put them. Maybe they would remove them for you if they are free for the taking.
mybrownthumbz6 thanked Tiffany, purpleinopp Z8b Opp, AL
Tiffany, purpleinopp Z8b Opp, AL
2 years ago
About to leave but should also say that the dirt under this plastic and rocks is likely to be horrible. If you do remove the covering, adding a layer of several inches of compost under several inches of mulch would be the best way to let it self-rehabilitate over winter.
mybrownthumbz6 thanked Tiffany, purpleinopp Z8b Opp, AL
mybrownthumbz6
Original Author
2 years ago
There are beds with these rocks around the entire house, so that's disappointing. :(
ken_adrian Adrian MI cold Z5
2 years ago
as to the depth of the bulb under the SOIL ...

lets say if a tulip should be planted 6 inches deep.. 3x its diameter ... and the flower should be 12 inches tall ... if you were to plant it extra deep.. the flower .. genetically programmed to bloom at 12 inches.. may end up shorter ....

this isnt get your ruler out precision ... but just dont get carried away on depth ... measure your hand trowel.. they used to be 6 inches.. and that would be a good guide to soil depth ...

also.. a common measuring idea was to know your bulb sizes ... e.g a good tulip is about 2 inches.. so plant the bottom at six ... with the tiny ephemeral ... that are an inch or less .. just go 3 or 4 inches ... always add you big city location .. in my ground freeze MI ... you need the depth so they dont heave out of the ground in winter ... and some depth helps hide them from the vermin .. aka.. squirrels ... etc ...

basically wing it.. but dont get carried away ...

the rock is more an issue whether they can push thru it.. without tearing themselves up ... so if it were me.. i would leave small circles of bare earth.. so it was real easy ... it might mean a little weed pulling but its usually worth it ...

what they all said about using man made fabric on top of gods soil ... if he meant you to use a plastic product.. the flowers would be plastic ... understand.. that a vast majority of seed is airborne ... so minutes after you lay it down.. weed seed is accumulating on top ... and as detritus accumulates on top.. the weeds will grow right down thru it .. and you cant pull them out ... hindsight is 20/20 ... and most of us learned the hard way ....

also roots need air as much as water ... and the fabric can interfere with air movement.. as well as proper water movement. ...

just pick an area... and get it out of there.. and plant your bulbs ... the removal project for the whole garden does not have to be all done tomorrow.... but its better if you get it all out.. sooner or later ...

ken
mybrownthumbz6 thanked ken_adrian Adrian MI cold Z5
mybrownthumbz6
Original Author
2 years ago
Great information, Ken. Thank you! I’m all about silver linings, so at least the landscape fabric will make it easy to remove the rock. I have the perfect place to start.
robert567
2 years ago
One problem I have with trying to plant up to 8 inches deep like is recommended with many "bulbs" is that the soil is compacted clay down there, and you are setting the bulb in a hard soil spot that may not drain well. So many end up 5-6 inches. Don't really want to dig up whole areas just for bulbs, and I like to stick plants in unused spaces. The bulbs figure out how to grow,... or not. Most seem happier being ignored anyway.