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Question about spacing of plants and shrubs

Harriman, TN

I was wondering how to space plants to allow a lush, full garden without overcrowding? And how underplanting fits into spacing?

1) I buy flowers in pots that say to plant 3 feet apart. I've noticed that the plant information says that they grow 3 feet wide, so I usually calculate 1& 1/2 feet on either side of the roots. Is this planting too close together? If I plant 3 feet apart, there seems to be a lot of room for weeds to grow.

2) I followed this same plan with bulbs (If it says to plant 3 feet apart, but they are only 18" across, I plant them about 2 feet apart), but I think I've made a mistake and know why they say to plant so far apart...bulbs multiply! Will the potted plants I bought in scenario 1 multiply also?

3) I bought a camellia shrub and a burning bush. The burning bush said to plant 3 feet apart, the camellia 5 feet apart. Instead of planting them 8 feet away from each other, I went 5 feet (because the burning bush will grow 4 ft wide, and the camellia 6 foot wide). Is that ok, or too close? I want a hedge like effect.

Finally, if you have to plant with space between, can one still underplant? My roses look so bare with nothing between them, and one is a climbing rose so it's pretty narrow, and I wanted to plant lambs ears between the two bushes, but I have them correctly spaced apart. If I plant lambs ears, would they compete for nutrients, or would it be ok?

I'm sorry for such a technical and kinda boring question, but I'm terrible at math and a little terrible at patience. I see in my head what the final garden should look like, and I think I might be overplanting to get that effect instead of waiting for my garden to spread! It's just that it's been over 3 years, and my garden still looks scraggly!

Dublin, CA(Zone 9a)

For shrubs, you definitely do need to consider proper spacing since they will be in your garden for a long time, and I'm assuming you don't want to have to go around in a few years and dig them all up and move them when they're too close together. I think your spacing on the camellia and the burning bush will be fine--if the camellias can be planted 5 ft apart, then planting a camellia 5 ft away from a plant that won't get quite as big shouldn't be a problem. Here's how the math would work on that one...if the camellia needs 5 ft space, that means it needs half of that or 2.5 ft on the side next to the burning bush. The burning bush needs 1.5 ft on the side next to the camellia (half of the 3 ft spacing they told you). So you add those together, and 2.5+1.5 gives you they need to be planted 4 ft away from each other.

For annuals that you're going to be replacing every year, you can plant a bit closer than they suggest to give a fuller effect--they're only in the garden one year anyway so you don't have to worry about the long-term effects of having them planted too close. Perennials it depends--if they're ones that don't spread much you can cheat a bit with them too, but if you cheat too much then you may end up having to move some. Or even if they do spread, you'll have to divide them eventually anyway. Perennials are a lot easier to dig up and move so again it's not as big of a deal as with the trees/shrubs, but you don't want to put them way too close because overcrowding can lead to disease issues.

For your plants that are supposed to be planted 3 ft apart, you're right about needing 1.5 ft on each side, but keep in mind if you have 2 plants next to each other, they both need 1.5 ft, so added together that means you need them to be 3 ft apart to allow them both to have their 1.5 ft. Or if you're going to cheat and plant things closer than that, just be aware that there will be more trimming/moving in your future than if you follow the rules (I would probably do at least 2 ft of spacing rather than 1.5 unless these are really slow growing plants). And as I said before, I would not cheat at all on trees and shrubs.

Dublin, CA(Zone 9a)

Should also add that all the measurements I mention above would be from the center of the from the center of the camellia to the center of the burning bush should be 4 ft, and with your other plants it should be 3 ft from the center of one to the center of the next. Not sure that was clear in my other post.

Harriman, TN

Ecrane3, Thanks so much! It relieves me to find out that I've done the math correctly in most cases. I'm a bit worried about the perennials because I think I went, "ok these say 3 ft apart so I'll plant them 1.5 feet apart on each side" not thinking that the next plant over also requires it's 1.5 feet on each side (so it would be 3 feet apart anyway!) I'm definitely going to be more careful in the future! Moving plants around can be a pain (though fun if I want to try new things).

What about underplanting? Yesterday, I used string to make a circle where the burning bush and the camellia will spread out, and it just left a couple of feet at the foot of my bed. I thought of small shrubs like azaleas, rhodenderons, peonys, or hyrangeas, but I'm afraid that would look crowded, especially if the small shrubs spread out. Perhaps I should stick to annuals?

Now I just have to worry about the height factor. I was figuring out that the camellias would be 6 feet wide, but forgot they would also be 6 foot tall, which may hide my front porch completely! I may have to move them after all! Better now than later I guess!

3 years gardening and still learning every day!

Dublin, CA(Zone 9a)

If you're trying to fill in gaps between shrubs that will fill in eventually, I'd recommend annuals or maybe some perennials that you won't mind pulling out in a few years. I would not fill in with other shrubs--if you want some smaller shrubs in the bed that is great, but you need to plan the correct spacing for them.

Casper, WY(Zone 4a)

Lamb's Ear is vigorous in growth and will rob nutrients from your roses. They also tend to spread, and look shabby when dormant in the winter. The flower stalks are 12 to 18" above the plant and not very attractive.

Roses need good air circulation to prevent disease. If you must plant something around them, consider low-growing/creeping Sedums. They are shallow-rooted plants and don't need much in nutrients. Some spread/creep, but easily controlled. Others forms a mound. Most bloom in June and July, depending on variety. There are creeping Sedums that grow just 1" high, others to 4" or more.

Another choice is perennial Delosperma (iceplants) which bloom all summer long and remain under 4" high. There are several varieties to choose from.

Yet another idea is Sempervivum tectorum, the common hen and chick. They stay put and produce offsets that will cover space. These too are shallow rooted and don't neeed much nutrients. I use this variety to keep weeds down.

My roses have a ring around them made from brown lawn edging I bought at Home Depot. The ring is filled with wood mulch to keep the soil cool and weed free. Also protects the base during our cold winters.

Portage, MI(Zone 5b)

I also have problems with Lamb's Ears being invasive. Boy, this is sure a plant you only need to buy one of. If you let it go to seed you will have it popping up everywhere forever. Year ago I had a huge patch of it flanking my main path in the cutting garden, and when it flowered, it was buzz buzz buzz ---- so many bees I couldn't use the path. My conclusion about Lamb's Ears is that I let seedlings grow if they pop up in innocuous or desirable places, but if they are too close to something they get lifted and either composted or transplanted. And once they get older, I lift the clump and put it in the compost pile. The new plants look fresh and attractive; the older patches are unattractive, especially early in the season. (I do like the flowers even though they are not flashy. . . and generally I like to help the bees.)

What I am now toying with for around roses is to let Myosotis (forget-me-not) and Alyssum self-sow here and there. I have experience with the Myosotis in the garden. Alyssum i have only grown in containers on the patio, but I have read it will self-sow. I've bought a flat of it which I will plant all along the front of my "big border" where I don't mulch so heavily, and i'm hoping it will self-sow in front of perennials & roses. (Nigella and larkspur and cleome are other self-sowing annuals I am fond of, by the way.)

One thing about spacing: Sometimes I will plant like items a little closer to each other than recommended, but leave the recommended spacing between unlike items. So for example, if the border has 3 of A, then 5 of B, I leave a bigger gap between A and B, but the A's are a bit close to each other and the B's are a little bit close to each other.

And the consideration of whether you'll be transplanting regularly is a big consideration. It's easy to lift perennials (especially if you have a helper), but shrubs are really hard to move.

When you calculate your spacing, think about whether it's near the edge of the border & will it eventually interfere with mowing and/or people walking by on the grass or on a path.

My burning bushes, planted in the 1970's by the first owner of my house, have a spread of 10 or 12 feet, by the way. You may want to verify/research the mature size of the exact cultivar you bought. A long row of them was planted in a lava-stone border about 30 inches wide. Talk about planting mistakes! The 30-inch border was way too narrow. Stone mulch is always a bad idea, and lavastones are the worst. And they used plastic under the lava stones, eegads. We get all kinds of burning-bush seedlings under the entire spread of the old shrubs, including in the lavastones, grass won't grow under the overhang of the shrubs, the underground sprinklers spray water which hits the overhanging branches and thus is prevented from going out over the lawn they way it is supposed to, etc. I guess I could prune them way down, but I really don't like the look of shrubs which are pruned to an unnatural size and shape. My books about pruning indicate it's better done to thin and rejuvenate rather than to make a shrub something it's not.

Casper, WY(Zone 4a)

I never had problems with Lamb's Ear reseeding since I remove the flowering stalks. However, they seem to spread anyway, seeds or no seeds. I'm cleaning and weeding my borders and they are (Lamb's Ear) going into the dumpster.

Ella If you are planning to plant the perennial form of Alyssum, they don't self sow much. They are more of a sub-shrub. The annual Alyssum does self-sow freely.

You can prune any shrub and still have it look natural. You can also make a shrub grow in any direction if you prune it correctly. It all depends upon where you make the cut. I know what you mean about branches interfering with watering. I had the same thing and got rid of the branch.

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