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As if I haven’t used botanicals enough in my art & design! How amazing it is that capturing nature’s form can be so beautiful! I am not going to tell you how… just kidding! Here we go; Botanical Relief Casting in plaster (and concrete as well)

Simple Supplies:

I was so happy to realize that I didn’t need anything that special for this. Doesn’t everyone have some plaster of Paris and plasticine at home? Simple children’s modelling clay works great for this project. This would also make a great project for summer camp as it will help create an awareness of nature and easy materials to use.


  • Modelling Clay (oil-base Plasticine)
  • Botanical Specimens
  • Rolling Pin
  • Wood Thickness spacers (not shown) opt
  • parchment paper
  • clay cutting tool (knife or similar)
  • Stiff board or tile
  • Frame shape (may use pre-made containers)
  • Plaster of Paris (or for harder casts Hydrocal)

The Pretty Plants:

I have a simple garden with a lot of variety but it’s by no means huge! This art form uses the form of the plants so it is better to choose ones that have some good texture or interest. There really are no rules! Once you start you will want to try them all! It is even interesting to show the roots or the bulbs! Try to have some type of design plan… Hint: if you can’t use the plants right away stash them in a container in the fridge.

The Frame Shape:

You can make any frame shape that you like… For simplicity I like to up-cycle some containers so that I have less ‘futzing’ with wood pieces. I also like them to be somewhat flexible to allow easy removal after casting.

These are a collection of my ‘frames’; store-bought cake container, storage containers cut, and even a chocolate box with middle cut out. I like that they are quite exact and can be cleaned. They are also transparent for some ease of use later…

Step #1 Make the base

Flatten an area of the clay with the rolling pin to a uniform smooth thickness on top of some paper or thin card board. This is important later so that you can lift the clay! The clay does not dry out and will be softer if it is warmer. You can use some heat like the sun to make it easier to flatten. If you like to use some strips to ensure consistent thickness at the edges that helps too! I plan to use some 1/2″ wood strips. Make sure the clay area is larger than the frame you want to use.

Step #2 Imprinting the design:

Arrange the botanicals as you like on your readied base of rolled modelling clay. You can place them all or work one by one. I like to arrange how they curve etc and hold in place before rolling over with the rolling pin. A sheet of parchment paper will help to make sure it does not stick. If the material is quite stiff and thick you may need a stiff board to push down the botanicals. I use a piece of clear plastic so I can see the design through.

Hint: the back sides of the leaves usually have more texture so face them down. If you want to make a change you can start over since it’s just reusable clay that does not dry, just flatten well again.

Once you rolled out the specimens they will be pushed into the clay. Flowers are nice but are be very very thin so the impression is very subtle. These bleeding hearts are quite dimensional! Be careful to keep the background as flat as possible for neatness.

Step #3 Pulling it out

I love the Bleeding hearts as they do have some interesting form in the flowers but there are many many more as well. Checkout all the kinds of weeds around… Spring & early summer usually has much budding going on.

Once you are happy with the design and have tested how it fills the frame carefully pull out the botanicals. They do come out quite easily since the clay is oil based and the plants are not. It is amazing how much texture appears! Use a low light source to see the details best. Use some tweezers or toothpicks if small parts get stuck.

Step #4 Shape of the frame

Whatever frame shape you decide can now be pushed into the clay. This will hold the plaster and create a mold so make sure it is well imbedded. If needed fill any of the openings like the stems that could leak with some clay bits from the outside.

Step #5 Pour your plaster

Mix up enough plaster to fill about 1/4 inch or more of the framed relief you have made. It is not vital to be a specific thickness. Some plaster is softer than others. Some also seems to have more bubbles…

Note: I have moved from using the cheap DAP plaster (as it was having many bubbles) to Hydrocal as it is much harder and less bubbles. You may practice with plaster to get the hang of it. Ultracal is even harder if you choose. I will also be casting in concrete… (soon)

Mix the plaster by first filling the water (flexible vessels like sour cream containers work well) and then keep adding the plaster until it sinks no more. Wait until it absorbs the water and then stir until smooth. Tap the container to rid of bubbles. Pour into the prepared frame.

It is also important to keep things level for uniform thickness. Lift the filled piece and tap it (lift entire stiff board) to make bubbles rise. The stems are quite thin voids so bubbles need to escape there. I have found that I prefer Hydrocal over plaster of paris since it is much harder.

Step #6 Pull from mold

I hope you remembered to put the clay on top of something flexible like paper. To lift the mold carefully pull the clay back from the plaster. You can slowly curve it away from the plaster form. Be ready to be amazed! ‘Or realize that you need to get all the bubbles out of the plaster. If you are careful when pulling the clay off the plaster you can usually cast another one from the same clay…

Since the plastic ring (from store-bought cake cover) is flexible and slightly tapered it come off easily. Any imperfections can be sanded with sand paper (do wear a dust mask for the plaster dust)

I never tire of how how much detail nature has! Now there is even much more reason to slow down and really look. So many plants have interesting shapes and textures not to mention when they have seed pods etc.

Flowers are very pretty but quite delicate. It may take a bit of extra pressure since the flower heads are thicker. Take a walk through the wild flowers and weeds; there is so much texture design that Mother Nature offers you.

This is my climbing hydrangea with spring buds. As with any art there is a million ways you can arrange and design the piece.

I am no stranger to using leaves but I had never realized the tactile amount of detail. I am now obsessed (no surprise) to make a huge variety and cast them in … CONCRETE! Yup, you guessed it! I am hoping to have some up for sale soon since I probably have too many!

‘And I haven’t even added colour yet! I do like the simplicity of colourless since then it’s about the relief textures. What do you like best? Colour or no colour? Plaster or concrete? Please add your comment below

Lots of effort and supplies go into making a process that works… I appreciate any sales of these through my shop

I'm an artist & I make things... all kinds of things.

This Post Has 47 Comments

    1. It really makes taking the dog for a walk more interesting. No wonder why the neighbours always wonder what the heck I’m bringing home now!

  1. C’est beau ! J’en suis ébahie. Tant de beauté. Je me demande si la grande simplicité d’exécution ne demande pas aussi une réelle dextérité. Une “patte” que tout le monde n’a pas. Mais, c’est un défi a relever et je vais essayer. Merci pour vos explications si claires qu’elles donnent envie !

    1. It’s beautiful ! I am amazed. So much beauty. I wonder if the great simplicity of execution does not also require real dexterity. A “paw” that not everyone has. But, it’s a challenge and I’ll try. Thank you for your explanations so clear they make you want to!” As long as you keep it simple and watch the details it is easy. I like that it can be flattened and redone.

  2. Oh how I LOVE these! But can’t wait to see what will result next when you add colour too. Maybe just hints of colour so as not to detract from the beautiful relief patterns?

      1. Agreed. Nothing too dramatic so as not to distract from the relief.
        On the other hand, I love everything you do so maybe try both- dramatic & subtle.
        Looking forward to seeing how it all comes out.

      2. Can’t wait to see your technique of adding colour and antiquing. Thank you for sharing your wonderful talent.

  3. This might be my favourite project yet! But then I ALWAYS think that with each new posting. Maybe it’s a matter of love the project you’re working on? I would need to see a coloured one for comparison but I love the focus on texture too. Do we have to choose?

    1. No, you can have both! Oh, so many options of colour AND then so many plants! You should see the stacks and specimens in the fridge! This artist ‘detail-brain’ of mine is obsessed…

  4. we LOVE concrete work or hypertufa or ANY concrete molds. These are perfection. My husband and I [as I am disabled] will make these beautiful molds for stepping stones.
    Thank you. I have a file of yours in my yahoo email so I can keep aLL your great ideas.
    Thank you again for another fun idea.


    1. It may but I think it starts to dry and and it may bond with the plaster. The modelling clay is oil base so it doesn’t stick and also lets some of the deep details pull out since it’s not rigid.

  5. Hi there. I’ve seen this on FB but as usual you help us understand it better. Thanks for the step by step. Pity I’m in South Africa because I would’ve loved to meet you in person, maybe some creativity will rub off.

  6. Thank you for generously sharing your creativity and expertise. This project is going to be for a very special person in my life. One question..please when peeling the clay off the plaster , I’m assuming you have flipped the piece upside down? Do I need to wait for the plaster to harden first?

    1. You need to wait until the plaster is quite cured! Plaster is softer than hydrocal. I think one batch I had from a hardware store was old as it just didn’t behave. Yes you need to flip it or at least pick it up; hence the sheet of some paper or so under the clay. The clay is pulled off the plaster in a curving way. It also helps that the clay is not too thick so ‘curving off’ is easier. Plaster is pretty cheap so if you get too many bubbles you can flatten carefully again and pour again. Good luck!

  7. The plastic containers that you use do you cut the bottoms out of the containers so you can pour the liquid onto the clay.

    1. Yes, the essentially end up like a ‘frame’. You can use wood too but I like the flexibility and precise shape of the plastics. I start the cut with a knife and then some heavy scissors…

  8. Hi Barb,

    I’ve been trying this out with DAP and I’m finding mine are coming out with a chalky residue, even when fully dry. Also the back seems softer than the front (if I were to try to draw on it, the pen scratches through the surface). I’m adding 2 parts DAP to 1 part cold water, waiting a few moments and mixing. Is there something I’m doing wrong? Is it supposed to be chaulky to the touch?



    1. I find that the plaster will continue to let dust off. I was not really happy with the normal DAP Plaster so I got some Hydrocal from a local pottery supply. WAY better and no dusting. I also found that maybe the DAP I got from one store could have been old as it was worse than the others. Sitting for long in humidity can have an effect on it. I also believe plaster made for artists is also better. Hope that helps! Don’t despair…

  9. I’m so excited! I just got the last of my supplies today, including plant cuttings, and will be trying it tomorrow.

    1. Good luck! As with any new craft, I like to get the hang of everything so I do small tests! I have been casting like crazy and will have a bunch up in my store soon!!! I love it!

  10. My castings (usingHydrcal) are coming out with missing spots. I’ve tried so many things to get it complete but tapping, shaking the mold and brushing in after pouring are not working.

    1. Sometimes it can happen more if the mix is too thick as then it doesn’t flow as nicely into the details (if unsure, mix a tiny bit and just pour a small puddle to see if it improves). When pouring it helps to pour in a continuous stream as well. If it’s only a couple spots you can mix a tiny amount and use a brush or small tool to fill in the missing gaps afterwards. ‘Hope that helps!

  11. I love this idea and they look beautiful. I would like to know if regular construction plaster can be used. Purchased a large bag a while back and don’t know what to do with it now. I know I bought it with the intentions of making something I saw on your website but I can’t remember what it was lol.

    1. I am not sure exactly what type/quality of plaster you have. I would take a bit and mix it up and pour into something shallow (plastic tray or like). Let it set and test for how strong it is. I think some of my plaster that I bought at the hardware store was old as it didn’t have the strength that the other did. I hate putting time into something that breaks.

  12. Hallo
    I love your work and it looks so achievable but I find it difficult to keep the clay smooth and flat as I push in or roll the flowers… it smudges and wrinkles. If I disturb the clay and try to smooth it, it gets worse
    I have tried botanical bas relief twice and realise my mistakes with the consistency of the plaster of Paris which has to be just ok.
    I really want to make it right but maybe I am just clumsy or it is not as easy as it looks.
    Do I just keep rolling up the clay then rolling it out until its smooth or am I making hard work of it?
    So sorry to be negative.

    1. Keeping the background clay flat is a bit of a challenge so I make sure to start with a very flat rolled piece (rolling pin). I did try rolling it with the rolling pin and having some strips of wood to keep the thickness consistent. Parchment can also help keep it flat. Another option is to not try to be so perfect and embrace a more rustic background and edge. Imagine even using some interesting texture for the background. The temperature of the plasticine can also affect how easily the background gets damaged. If I plan to make a mold from the plaster then the plaster can actually be sanded and fixed in spots.

    1. Yes! See here for the mold making. Is that what you meant? I did try the silicone caulking/cornstarch as well and it did work but not as nicely detailed and caution for how fast to work and the pressure applied.

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