How to Plant Hostas in Rock Gardens

Planting hostas in your rock garden exemplifies the practicality of both the hostas and the rocks.  Find out what you need to know to make the perfect rock garden at home.

Hostas are drought-tolerant, robust, and shade-loving plants. They can live in zones 3-9 with over 70 species, and over 3,000 variations, the possibilities are endless. Hostas and rocks are a sensible combination because of the hosta’s need for well-drained soil and the overall low maintenance of the two together.

Wondering how and why you should plant hostas in your rock garden? Keep reading to see the breakdown of various styles, tips, and tricks to utilize your hostas and rocks to their fullest potential.

A hosta garden at the RHS Chelsea Flower Show in 2017

Let’s be Practical – Hard Work – Low Maintenance

Rock gardens and hostas work very well together because of their low maintenance, adaptability, and complementary colors. Let’s break this down.

Rock gardens themselves can fight off weeds by creating a sturdier layer of protection than wood mulch. Staying on top of the weeds, especially in the beginning, is a must, but overall, there is less weeding than using wood mulch.

Now let’s add hostas into the mix. If appropriately planned, mature hostas will create another layer of protection. Planting the hostas at least eight inches apart but more importantly depending on their mature width size will allow for the hostas leaves to touch, not letting sunlight through I.E., no weeds. Not to mention hostas only need about an inch of water once a week.

The adaptability of rock gardens comes into play when thinking about things like paths, accents to fountains’ or significant features in the yard, or hills and slopes. The beauty of rocks is the ability to create their own retainers by stacking on top of each other or merely placing larger ones as borders.

Video – Rock Garden Tour

The adaptability of hostas is just as equally impressive. The fact they are shade-loving allows for almost any space in your yard to become a garden. But do not let this fool you hostas are tough, and many varieties will do perfectly fine with more sun. 

Rock gardens have a natural feel to them when done right. The earthy tones, the depth of various rocks, and the unique number of shapes a rock garden can be.

  • Having too many contrasting colored rocks or even just types of rock will break the natural look of a rock garden.
  • When setting up rocks, it’s a rule of thumb to go from large to small. This will help with not overcrowding the large rocks.
  • Be creative when making a rock garden; they are not meant to be raised square planting beds. Some ideas are listed above. Also, use them to your advantage if your yard is sloped or has an area that acts as a water funnel they can be used as little river beds.

Hostas have such vibrant and a multitude of deep colors.

  • Be careful having too many different species of hostas. Doing so can look chaotic and less natural.Line 2
  • Using hostas as a border around the rock garden is a great idea, but keeping them to one species or at least under three is a good idea.

What Kind of Rock Will You Use in Your Rock Garden?

Rock garden with reddish granite gravel and a green-yellow hosta

There are two ways to go about a rock garden starting from scratch or utilizing what you have. A chart of various rocks, sizes, drainage abilities, and price are further below. In the meantime, let’s discuss a simple rock garden using one or two types of smaller rock to a more complicated rock garden with multiple types and sizes of rocks. 

There are many different ways to plant hostas in rocks. My first suggestion is to work with what you have. Below is a short list of standard gravel mulch used in a rock garden.

  • Pea Gravel
  • Lava Rock
  • Brick Chips
  • Crushed Granite Gravel
  • River Rock
  • Marble Chips

Using one of these rocks is what a simpler rock garden would look like with a possible larger river rock or stone bordering the outside. Matching the environment can help determine what rocks you should use; this will create a natural feel to your garden.

Red lava rock

A more complex rock garden will have larger rocks within them. They will usually have things like retaining walls of uncemented rocks, rocks stacked aesthetically, or create mounds to be planted on, and utilizing rocks to create patterns. Either way, here are some extra rocks typically used.

  • Large River Rocks
  • Flagstone
  • Boulders 

When making a rock garden, it is a good idea to use decomposed granite. Decomposed granite is a fine crushed stone resembling sand. DG can be important for any rock garden. What it can do is be added to the rock garden to mimic wood chips. It will provide nutrients such as calcium, magnesium, and iron; it will also hold moisture. 

Another view of the hosta garden at the RHS Chelsea Flower Show in 2017

Hostas in Rock Gardens – So Many Choices

We will get into the how-to of designing the overall garden, but it is crucial to explain the how-to of planting and selecting the right hostas. Later in the article, a chart will show various types, mature sizes, and the amount of sun needed for each hosta. What we will go over now are some tips and tricks for growing hostas. 

It’s important to differentiate between the morning sun and the harsher afternoon sun. The afternoon sun will come with a lot more heat. This is when the burnt-looking edges of your hosta will come into play. If you are worried about getting too much afternoon sun in an area, choose lighter shades of rocks they will hold and reflect less heat than the darker shades.

  • Work with the sun by watching as the sun goes over your yard, mark or remember where the most sun and shade is, plant according to the hostas’ needs.
  • Work with rocks and hills, South facing slopes or the South sides of large rocks will get more sun while the North-facing side will get more shade.
  • Make sure to plant at least four weeks before the first frost, usually August, or after the last frost, the end of May.
  • The ideal soil ph for hostas is between 6.5-7.5
  • If plants begin to show browning on the edges or dull leaf colors,  they need to move to a shadier area.
  • Hostas can be broken into five sizes, miniature under 10 inches, small 10-15 inches, medium 15-25 inches, large 25-30 inches, and giant 30 plus inches. Use the various dimensions to create shade or give more sun to plants that need it.
  • Hostas like at least four hours of morning sunlight with diffused sunlight throughout the day, this would be like shade under a tree not from a brick wall, but remember they are tough plants; this is not a necessity.

It’s important to differentiate between the morning sun and the harsher afternoon sun. The afternoon sun will come with a lot more heat. This is when the burnt looking edges of your hosta will come into play. If you are worried about getting too much afternoon sun in an area, choose lighter shades of rocks they will hold and reflect less heat than the darker shades.

Let’s Put it All Together – Sit Back and Watch it Grow

Like I mentioned above, natural looks for rock gardens are key to success. Mimicking the rocks in your area is a great idea. When placing rocks, make sure to bury them a third of their height in the ground. This will prevent the frost from dislodging them. The striation of the rocks should be going in the same general direction. Stacking rocks to form a small retaining wall can help get the hostas closer to eye level showing off their vibrant and neat designs. 

There is always worry in the first spring that your hostas are not coming up because you have done something wrong planting the garden. The link above my calm some of your worries.

Video – Small Backyard Rock Garden DIY

If you have the luxury of picking the spot for your garden, find out what type of hostas you want first. If they are heavier on the sun-loving side, then place the garden accordingly with a layer of sand or decomposed granite, topsoil, then Peat moss for shade-loving plants put a high nutrient compost then Peat moss under the rocks. 

You might be wondering what to do if your hostas are not flowering as you wanted them to or not like the pictures. If the perfect garden bed is in an area where you are worried and do not get enough shade, consider this.

 “ While shade seems essential for the production of the large expanses of hosta leaves, more sun is required to produce good flowers. Many hostas will grow in a great deal more sunlight than the conditions in which they are normally planted, provided they receive sufficient moisture at the roots,” Diana Grenfell and Micheal Shadrack’s book The New Encyclopedia of Hostas.

Here are some categories and examples you should look into before buying your  hostas for your rock garden. 

A block of well grown hostas in a nursery

Hostas For Your Rock Garden

Cultivar

Mature Size

Sun Amount

Average Price

Blue Mouse Ears

Miniature:
6 inches tall
11 inches wide

6-12 hours of shade

$10

Rainbow's End

Small:
10 inches tall
20 inches wide

8-12 hours of shade

$18

Blue Hawaii

Large:
25 inches tall
42 inches wide

6-8 hours shade - avoid direct sun

$15

June

Small:
10 inches tall
30 inches wide

4-6 hours part sun to morning direct sun

$15


Empress Wu

Giant:
48 inches tall
60+ inches wide

6-8 hours shade to 4-6 hours bright shade

$20

First Blush

Medium:
12 inches tall
24 inches wide

4 hours morning sun to 6 hours bright shade

$35

Hawaiian Luau

Medium:
18 inches tall
30 inches wide

4-6 hours of bright shade

$25

Out of the Fog

Miniature:
6 inches tall
10 inches wide

4-6 hours of bright shade

$25

Spartacus

Large:
36 inches tall
36 inches wide

6-8 hours shade to 4-6 hours bright shade

$18

Remember, these plants are tough, and they will be fine with direct sunlight as long as they get diffused sunlight throughout the day. If the leaves turn dull, this is a good indicator; it’s not getting enough sun. If the sun amount is more than enough the problem is probably not enough nutrients going to the plant.

Now consider the types of rocks you can work with when creating a rock garden. Don’t be afraid to find your rocks down by the river or in the backyard; these types of weathered stones and rocks are something you cannot buy in stores.

Colorful River Rocks

Rocks For Rock Gardens


Rock Type

Rock Size

Drainage

Price per yard

Pea Gravel

1/8 to 3/8 inch

Medium

$30

Crushed Granite Gravel

3- 4 inches

Fast

$50

Lava Rock

1/2 to 1 inch

Fast

$75

Brick Chips

3/16 to 1 inch

Fast

$40

Marble Chips

1/8 to 5/8 inch

Medium

$130

River Rocks

3/8 to 6 inch

Fast

$40

Flagstone

1 square foot or larger

Slow

$2 per square ft

Decomposed Granite

Similar to sand

Slow

$45

Prices vary depending on location. Many of these gravel mulches can vary upon size based on request.  

A selection of colorful pathway gravels

Related Questions?

Can you apply fertilizer to a rock garden?

Yes, dry granular fertilizer will work well. If possible, a very light rake will help the fertilizer fall to the soil. For detailed information on fertilizing hostas check our post How to Fertilize Hostas (A Simple Method)

Where else are good areas to create a rock garden?

Fruit trees do exceptionally well with gravel mulch, and the diffused sunlight will be great for a few hostas. Top off pots too; gravel mulch will contain moisture and add nutrients.

Can you plant hostas with roses?

Yes, you can. With careful planning and a little skill, you can have a rose and hosta garden. And of course, we have an article all about planting hostas and roses together.

DIY Hosta and River Rock Border

Let’s Wrap it Up

Rocks can give you a great canvas to use the perfect paint, hostas. The drought-tolerant perennial will be a low-maintenance pair to your rocks. They will grow tremendously and can live in parts of your; yard most flowers and vegetables will not grow. Take the opportunity to create your unique rock garden or spice up your yard with gravel mulch beds, but know that hostas are a great fit.